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4036 views
07:32 Sep-18-2005
Ed T.
RE: 2% or Really 4% Sensitivity

Whe using plaque type penetrameters, 2-2T is a typical IQI designation.

The first 2 refers to the IQI thickness which represents a percentage of the thickness of the part being inspected.

The 2T refers to the diameter of the hole that must be discerned.

Therefore, 2-2T indicates that the IQI thickness should be 2% of material thickness and that the required hole is 2x the IQI thickness.

What this means is that a 2-2T IQI in the radiograph is a means of verifying that the RT technique is capable of discerning a 2% loss of material and not a measure of size of disontinuity that can be located on the radiograph.

Now, the holes in plaque type penetrameters represent sharp boundaries, and small thickness changes (2%).
Flaws in the part may not have these sharp bundaries, and may not be as visible.

Therefore, the penetrameter is used to indicate quality of the radiographic technique and not intended to be used as a measure of size of discontinuity that can be located on the radiograph.

If you look at ASME, it gives you a range of thicknesses and not a 2% sensitivity requirement.



 
06:30 Sep-20-2005

N.Kuppusamy

Consultant, Level-III
United Testing Co. Pte Ltd,
Singapore,
Joined Jan 2003
13
Re: RE: 2% or Really 4% Sensitivity Hi friends,
2-2T and 2-4T etc are inedicating quality levels only. We can calculate Equivalent Penetrameter Sensitivity (EPS)only using mathematical formula.

Please refer to ASTM E1025-1998 Table-1 for Equivalent Penetrameter Sensitivity (EPS)and appendix for mathematical formula.
Regards,
nksamy
----------- Start Original Message -----------
: Whe using plaque type penetrameters, 2-2T is a typical IQI designation.
: The first 2 refers to the IQI thickness which represents a percentage of the thickness of the part being inspected.
: The 2T refers to the diameter of the hole that must be discerned.
: Therefore, 2-2T indicates that the IQI thickness should be 2% of material thickness and that the required hole is 2x the IQI thickness.
: What this means is that a 2-2T IQI in the radiograph is a means of verifying that the RT technique is capable of discerning a 2% loss of material and not a measure of size of disontinuity that can be located on the radiograph.
: Now, the holes in plaque type penetrameters represent sharp boundaries, and small thickness changes (2%).
: Flaws in the part may not have these sharp bundaries, and may not be as visible.
: Therefore, the penetrameter is used to indicate quality of the radiographic technique and not intended to be used as a measure of size of discontinuity that can be located on the radiograph.
: If you look at ASME, it gives you a range of thicknesses and not a 2% sensitivity requirement.
------------ End Original Message ------------




 


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