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1579 views
01:14 Jan-21-2006

Biju Varghese

Sales, Project Manager
Blue Star Limited,
India,
Joined Apr 2008
2
Defect width

Is it possible to know the width of the defect in butt weld using angle beam inspection scanning from one side?


 
04:12 Jan-23-2006

Uli Mletzko

R & D, Retired
Germany,
Joined Nov 1998
89
Re: Defect width ----------- Start Original Message -----------
: Is it possible to know the width of the defect in butt weld using angle beam inspection scanning from one side?
------------ End Original Message ------------

Do you really think about the 'width', that is, for example, the gaping or yawning of a crack, or could it be the 'depth' (extension perpendicular to the surface) or the 'length' (lateral extension) of a crack.

Volumetric flaws with smooth surface might be a different problem.

Regards
Uli Mletzko
NDT Group, Materials Testing Institute (MPA),
University of Stuttgart (Germany)




 
06:58 Jan-23-2006

René Sicard

R & D, R&D Manager
TecScan Systems inc.,
Canada,
Joined Jan 2006
5
Re: Defect width If you are referring to the defect extension perpendicular to the surface, an artificial focusing imaging technique called Multi-SAFT can be applied to angle beam inspection data. This method can provide information about the size and orientation of a defect. If you want more info about the subject, don't hesitate to contact me.

Regards,
René Sicard
TecScan Systems


----------- Start Original Message -----------
: Is it possible to know the width of the defect in butt weld using angle beam inspection scanning from one side?
------------ End Original Message ------------




 
06:41 Jan-24-2006

S.V.Swamy

Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex ,
India,
Joined Feb 2001
782
Re: Defect width ----------- Start Original Message -----------
: Is it possible to know the width of the defect in butt weld using angle beam inspection scanning from one side?
------------ End Original Message ------------
Dear Biju,

Your terminology has caused a little confusion. I think you are referring to the crack length. If so, I feel a focused angle beam (with the focal spot at the plane of the defect) will be ideal (we had such a situation in the case of a resistance butt weld), but it all depends upon the beam width and the size of the defect which you are trying to detect. I think we need a specific discussion here.

Best wishes.

Swamy





 
06:19 Jan-27-2006

Biju Varghese

Sales, Project Manager
Blue Star Limited,
India,
Joined Apr 2008
2
Re: Defect width ----------- Start Original Message -----------
: Is it possible to know the width of the defect in butt weld using angle beam inspection scanning from one side?
------------ End Original Message ------------

By Defect Width I mean the extension of defect in the direction of sound beam travel.


 
00:53 Jan-30-2006

William Blum

Consultant, Training, Level III Services
NDT Consulting Group Inc.,
USA,
Joined Nov 2000
89
Re: Defect width In short - no.

----------- Start Original Message -----------
: : Is it possible to know the width of the defect in butt weld using angle beam inspection scanning from one side?
: By Defect Width I mean the extension of defect in the direction of sound beam travel.
------------ End Original Message ------------




 
01:05 Jan-30-2006

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1185
Re: Defect width Biju:
For a practical weld inspection such a feat is not reasonable to expect. Perhaps in a very precise lab setup where the flaw can be definitely determined from both sides in a symmetric way you could estimate the width by a difference in travel time if the exit points from both sides were accurate to within a few microns (clearly not a practical option).

I have seen this type of "requirement" in workmanship-style acceptance criteria. It seems to occur when a Code writing body tries to make ultrasonics provide results that are identical to radiography.

An exmple is AS2885.2.
Ultrasonic inspection is described in Clause 19 and 19.2.8 states that acceptance criteria SHALL comply with Clause 22. AS 2885.2 has 3 tiers of assessment. Tier 1 is a typical Workmanship criteria. When you read AS 2885.2 you see the impossible is expected for UT.
22.2.7 Slag insclusions greater than 3mm width are unacceptable for isolated slag inclusions. When parallel slag lines exist and are separated by the width of the root bead they are considered a single indication unless the width of either exceeds 1mm when they will then be considered 2 separate indications.
22.2.8 Porosity is unacceptable if a dimension of an individual pore exceeds 3mm. Or if one of the pores in a cluster exceeds 2mm.

It is very unfortunate when Codes do not consider the differences between UT and RT. But just as annoying is when people try to make up stories about how their system can achieve the impossible instead of agreeing that the Code is wrong and making a sensible project-specific modification to the acceptance criteria.

Since they are made by people it is natural that there are errors and unintentional items in Codes...these are dynamic documents. Committees responsible for their content have a responsibility to correct things "quickly" when the issues are identified. But, it is my opinion, users are equally responsible to use common sense.

----------- Start Original Message -----------
: : Is it possible to know the width of the defect in butt weld using angle beam inspection scanning from one side?
: By Defect Width I mean the extension of defect in the direction of sound beam travel.
------------ End Original Message ------------




 


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