impact temperature reductions per Table UG84.2

[Ani18]

Hi experts i just want to know what will be the impact temperature reductions per Table UG84.2
(1) Base material thickness is 9.27mm.
(2) Deposited weld metal thickness - GTAW (4mm) & MAW(5.27mm)
(3) MDMT temp. is -31degree Celsius.

In my opinion it will be -50 degree C. is it correct for ,multi process impact specimen?

 

[david339933]

See UG-84(C)(5)(-b)
Temperature reductions are based on subsize specimens. You haven't given the size.

 

[Ani18]

Sorry, CVN specimen for gtaw weld metal 3.3x 10mm.

 

[david339933]

Why are you not using a full size specimen comprised of the weld metal of both processes?

 

[Ani18]

But as per UG-84(h)(5)multiple process welding procedure states separate sets of impact test specimen required from each process.

 

If asked to review your WPS I would reject it for applications where impacts are required.

Combining processes like this (with impact testing) is was a major loophole in the Code (except Sect. III), but while it is 'legal' it is was totally illegitimate technically, and so engineering judgment forces rejection. (Thanks for the UG-84(h)(5) update - they have finally closed this loophole. I have not been working with the latest edition).

Qualify two procedures, one for each process. I find that combining weld processes is not efficient for other reasons anyway - it only makes sense if all you ever weld is piping with either GTAW+SMAW or E6010+E7018, and with no impact testing.

This is quite apart from any Table UG-84(c) considerations for subsized specimens. Whatever you do, ensure your welder maintains alignment of the base metals and keeps angular distortion to an absolute minimum. If not your test coupons will be even more subsized and you could incur a greater temperature penalty.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Ani18]

Thanks man

 

[Ani18]

So the better option is to weld each process in a separte test coupon and impact test individually.

 

[david339933]

Not sure why you would reject this WPS. The basemetal is less than 3/8" thick, a full specimen is almost always preferred.
There is no update to UG-84(h)(5), it's been this way for years.
Some client specs may dictate that the WPS is impact tested as a multi-process when that is what will be used in production.

 

[Ani18]

So UG-84(h)(5) statement says welding procedure shall be qualified by testing sperate sets of impact test specimens removed from weld metal and heat affected zone .
Then how can I use a full specimen? Please explain
When sperate sets of imppact specimens are used for individual process then how should I calculate temperature reduction as per UG 84.2 if the thickness of test specimen less than 80% of material nominal thickness ? Is it as per UG 84 (C) (5)(b)?if yes then for a multi process what will be the actual material thickness? 4mm or 9.27 mm (do we have to consider process individually)

 

There is no update to UG-84(h)(5), it's been this way for years.

Not that many years. 2010 is the latest I have at hand and it is not in there.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Ani18]

So UG-84(h)(5) statement says welding procedure shall be qualified by testing sperate sets of impact test specimens removed from weld metal and heat affected zone .
Then how can I use a full specimen? Please explain
When sperate sets of imppact specimens are used for individual process then how should I calculate temperature reduction as per UG 84.2 if the thickness of test specimen less than 80% of material nominal thickness ? Is it as per UG 84 (C) (5)(b)?if yes then for a multi process what will be the actual material thickness? 4mm or 9.27 mm (do we have to consider process individually)

 

Weld two test plates, one for each process. At T = 9.27mm if you are careful, there should not be a test temperature penalty incurred.
Later you can combine the two processes into one WPS if you wish (or not).

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[Ani18]

Thanks man

 

[r6155]

And what do you do with UG-84 (i) Vessel (Production) Impact Test Plates?

Regards