NB-2540 examination of forgings

[men8th]

I have a forged pressure vessel head. If I invoke ASME III NB-2540 for examination of forgings and opt to use ultrasonic examination in accordance with NB-2542, the acceptance standards seem very vague.

The first thing that NB-2542 does is invoke Article 5 of Section V of the ASME BPVC. That is fine, but as far as I can tell, Article 5 does not define any calibration block requirements. If you look at, for example Article 4 (UT of welds) there are things like Figure T-434.2.1 which defines holes and geometry of the calibration block.

Are the acceptance standards for nuclear forgings really this poorly defined, or am I missing something.

 

[JR97]

I have a forged pressure vessel head. If I invoke ASME III NB-2540 for examination of forgings and opt to use ultrasonic examination in accordance with NB-2542, the acceptance standards seem very vague.

The first thing that NB-2542 does is invoke Article 5 of Section V of the ASME BPVC. That is fine, but as far as I can tell, Article 5 does not define any calibration block requirements. If you look at, for example Article 4 (UT of welds) there are things like Figure T-434.2.1 which defines holes and geometry of the calibration block.

Are the acceptance standards for nuclear forgings really this poorly defined, or am I missing something.

The acceptance criteria for NB-2540 inspections is a loss of back reflection. No calibration blocks are needed for a loss of back reflection inspection. If you have non-parallel surfaces, then the provision to use a DAC curve that provides equivalent sensitivity comes into play. The specifics would need to be worked out with your ANI.

 

[mfgenggear]

Op
Look carefully in the spec. Does it specify an acceptance criteria specification

 

[men8th]

The acceptance criteria for NB-2540 inspections is a loss of back reflection. No calibration blocks are needed for a loss of back reflection inspection. If you have non-parallel surfaces, then the provision to use a DAC curve that provides equivalent sensitivity comes into play. The specifics would need to be worked out with your ANI.

Thanks for your help JR97, that makes sense now.

 

[mfgenggear]

Generally there are two specifications
Procedure
Acceptance.
First specification out line or depicts which inspection is used. NDT.
Second defines what type of indications are and are not acceptable.
Contact your quality engineer for assitance