Another ASME IX base metal thickness question

[kingnero]

I'm used working according to EN/ISO standards for welder and procedure qualifications, however I'm trying to have a better understanding of the ASME IX philosophy.
Next question is a theoretical example, purely for my better understanding.

A V-groove butt weld, welded on a 1/2" plate, first two passes using GTAW (deposited thickness: 3/16"), fill and cap using gas shielded FCAW (deposited thickness: 3/8")
There are impact requirements.

I have two different answers for the range of validity of the base metal thicknesses, would someone please check if one of those is correct, or perhaps if there is a third possibility?

A
---
For GTAW: plate thickness from 1/2" (according to QW-403.6) to 1" (according to QW-451.1), max. deposited thickness is 3/8"
For FCAW: plate thickness from 1/2" (according to QW-403.6) to 1" (according to QW-451.1), max. deposited thickness is 3/4"

B
---
For GTAW: plate thickness from 3/16" (according to QW-200.4(a) and QW-451.1) to 1" (according to QW-451.1), max. deposited thickness is 3/8"
For FCAW: plate thickness from 3/16" (according to QW-200.4(a) and QW-451.1) to 1" (according to QW-451.1), max. deposited thickness is 3/4"

It would help tremendously not only to reply with "option A" or "option B", but additionally also to explain why. The train of thoughts is more important than the correct answer here.
Thanks in advance...

 

[david339933]

Ignoring that 3/16" GTAW + 3/8" FCAW is greater than 1/2" (9/16")....
It depends. A is correct if impacts are involved. B is correct if no impacts.

QW-403.6 is a supplementary essential variable...it only applies if impacts are necessary. See QG-105.

 

[david339933]

Sorry, missed that impacts are involved....therefore A is correct.

 

[kingnero]

Thx for your reply.
But why is the statement in QW-200.4 (a) not applicable in this case?

It is not uncommon to have a deposited weld thickness that exceeds the plate thickness, so I don't see a problem there?

 

[david339933]

Supplementary essential variables become additional essential variables.
QW-401.1 - "When supplementary essential variable QW-403.6 applies, it modifies only the minimum thickness qualified, not the maximum."

I'm not sure I understand the second part....reinforcement doesn't count.

 

[DekDee]

kingnero,
Try and get a hold of the CASTI - Guidelines to ASME IX.
Very helpful.
If you can't find PM me,
Cheers,
Shane

 

[kingnero]

@ david...: Thx, I'll see if I get any wiser with this info.

@ Shane, thx for the constructive reply ;-) Just had a quick look on amazon, it looks like it's no longer available. If I can't find the book anywhere else, I'll contact you.

 

[david339933]

It should be noted that this also applies to fillet welds when impacts are involved. The statement "All fillet sizes on all base metal thicknesses and all diameters" of Table QW-451.4 no longer applies...as per the general note of the same table.

 

[kingnero]

I figured that already, but thanks for the reminder. This is indeed something that could get overlooked easily.


EDIT: just to confirm, as ISO standard base their validity ranges in certain cases on the actual deposited weld thickness (as opposed to plate thickness),
weld reinforcment/excessive penetration does not count under ASME IX? So t1 + t2 must equal plate thickness T ?

 

[DekDee]

Kingnero,
David is correct - reinforcement is excluded from any weld thickness calculations in ASME.
Now, if you are working to ASME B31.3 with impacts then the goalposts have changed even more !
Cheers,
Shane