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Andres Romero
NDT Inspector,
Spain, Joined Jul 2019, 13

Andres Romero

NDT Inspector,
Spain,
Joined Jul 2019
13
11:44 Mar-18-2020
Reference block manufacturing

Hello, to make a reference block according to ASME V art.4 Figure T-434.2.1.
To work with Pahsed array
Notching is required. Is it totally mandatory? Is it a recommendation?

Sometimes notch interferes with TCG side drills.

Thanks

 
 Reply 
 
Paul Holloway
Consultant,
Holloway NDT & Engineering Inc , Canada, Joined Apr 2010, 255

Paul Holloway

Consultant,
Holloway NDT & Engineering Inc ,
Canada,
Joined Apr 2010
255
16:18 Mar-19-2020
Re: Reference block manufacturing
In Reply to Andres Romero at 11:44 Mar-18-2020 (Opening).

Hi Andres,

Unfortunately there are some things left in the ASME code which point to a time long past.

The notches in the basic non-piping calibration block are there only to help folks with analog instruments (30+ years ago) quickly locate the ID and OD surface positions. They are not for sensitivity, only sound path position. And of course, this would work only if the part they were inspecting was exactly the same thickness as the calibration block.

The position of the notches should not interfere at all with the side-drilled holes.

To use with phased array, the block really needs to be longer and/or have angled ends. These would eliminate the termination echoes that would otherwise interfere with the side-drilled hole signals and be much higher in amplitude, and thus cause errors in the TCG.

You can get around this, somewhat clumsily, by performing a "split-DAC" (actually a split-TCG, but most times I've seen it referred to as a split-DAC... same idea). This is where you break the PAUT calibration into sections by doing only the lower angles first, then perhaps one or two other angle ranges until you have completed the whole sweep. You do this to keep the termination echoes from interfering with the holes, but of course what happens is that when the machine joins the math up to create a curve, there is often a discrete "bump" on the TCG curve at the angle break points and makes this rather messy. As I say, it's clumsy.

The more common way to do it is use a different block. Blocks such as the PA No. 3 from PH Tool have angled ends and lots of length so you can perform the PAUT TCG calibration in one shot. But they don't contain the notches (which you won't use anyways). Keep in mind that by the letter of the law, a block such as this does not completely comply with all the requirements of Figure T-434.2.1. The holes are the correct size and positions, but without the width (6"... which is pointless) and notches, you can't say for 100% certainty that an auditor wouldn't call you out on it. But this would apply for *any* block used for similar purposes (PACS etc.).

PA No. 3 here: https://store.phtool.com/phased-array-ultrasonic-test-blocks/pa-calibration-block-no-3-3-4-thick/phased-array-cal-block-no-3-3-4-thick-1018-steel/

Best regards,
Paul

 
 Reply 
 
Andrés Romero
NDT Inspector,
Spain, Joined Jul 2019, 13

Andrés Romero

NDT Inspector,
Spain,
Joined Jul 2019
13
00:17 Mar-20-2020
Re: Reference block manufacturing
In Reply to Paul Holloway at 16:18 Mar-19-2020 .

zoom image



Hi Paul,
Thank you very much for your reply. I have made the block of the image that I send attached.
It has no notch. It does not fully comply with ASME, but what problem can I have if I include this block in a report, as a sensitivity block for PAUT.
sorry, my english is not good.
 
 Reply 
 
Paul Holloway
Consultant,
Holloway NDT & Engineering Inc , Canada, Joined Apr 2010, 255

Paul Holloway

Consultant,
Holloway NDT & Engineering Inc ,
Canada,
Joined Apr 2010
255
02:14 Mar-20-2020
Re: Reference block manufacturing
In Reply to Andrés Romero at 00:17 Mar-20-2020 .

The block is not even close to being ASME compliant. The thickness is wrong, the hole sizes are wrong, and the placement of the 3mm holes are wrong.

If I were you I would not get this block. Just get a regular ASME basic block. Why make your own?

 
 Reply 
 
Andrés Romero
NDT Inspector,
Spain, Joined Jul 2019, 13

Andrés Romero

NDT Inspector,
Spain,
Joined Jul 2019
13
14:02 Mar-20-2020
Re: Reference block manufacturing
In Reply to Paul Holloway at 02:14 Mar-20-2020 .

Hi Paul,
Thank you very much for your reply.

3mm if error.

I have some questions
Why is the thickness incorrect?

ASME says:

Over 2 (50) through 4 (100) 3 (75) or t 3/16 (5)

75 mm or T (T=80 mm)

I think the 5mm holes are correct.

GENERAL NOTES:
(a) Holes shall be drilled and reamed 1.5 in. (38 mm) deep minimum, essentially parallel to the examination surface.

drill deep is 40 mm

thank you very much for your help

 
 Reply 
 
Paul Holloway
Consultant,
Holloway NDT & Engineering Inc , Canada, Joined Apr 2010, 255

Paul Holloway

Consultant,
Holloway NDT & Engineering Inc ,
Canada,
Joined Apr 2010
255
19:38 Mar-20-2020
Re: Reference block manufacturing
In Reply to Andrés Romero at 14:02 Mar-20-2020 .

The standard block thicknesses in mm are:

19, 38, 75

ASME doesn't specify a tolerance on the thickness, and although using an 80 mm block instead of 75 is probably perfectly fine, your auditor may not see it that way.

The 5 mm holes are correct, but the 3 mm ones are too small and are in the wrong depth locations.

The 5 mm holes are too close to the end of the block, so you will definitely end up with termination (corner trap) echos that will cause problems.

Hole length is good though (min 38 mm)

 
 Reply 
 
Andrés Romero
NDT Inspector,
Spain, Joined Jul 2019, 13

Andrés Romero

NDT Inspector,
Spain,
Joined Jul 2019
13
21:45 Mar-20-2020
Re: Reference block manufacturing
In Reply to Paul Holloway at 19:38 Mar-20-2020 .

zoom image

T-434.2.1

Hi Paul,
I do not agree with the thickness.
ASME 2019 T-434.2.1

Weld Thickness - Over 50mm through 100 mm.
The calibration block can be 75 mm or T
T is the thickness of the piece to inspect.
attached image

Regards
 
 Reply 
 
Paul Holloway
Consultant,
Holloway NDT & Engineering Inc , Canada, Joined Apr 2010, 255

Paul Holloway

Consultant,
Holloway NDT & Engineering Inc ,
Canada,
Joined Apr 2010
255
22:06 Mar-20-2020
Re: Reference block manufacturing
In Reply to Andrés Romero at 21:45 Mar-20-2020 .

Hi Andres,

Sorry, I thought you were trying to substitute a block for a regular 3" ASME block.

If your test piece is 80 mm thick, then yes of course your calibration block can be 80 mm.

Cheers,
P

 
 Reply 
 

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