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Up Topic Welding Industry / Technical Discussions / Impact tests to ASME VIII Div 1
- - By Shane Feder (****) Date 03-18-2009 20:32
Hello guys,
I have been learning quite a bit on the forum about impact tests, something I have not had a lot of previous experience with.
I am familiar with the thickness requirements for ASME IX and B31.3 WPS qualification when impacts are required however not sure on ASME VIII Div 1.
I am currently reviewing a PQR / WPS that has been signed off by an AI but I am unsure if it is correct.
PQR plate thickness - 49 mm (2")
1 x PQR GTAW/FCAW impact tested
1 x PQR SMAW/SAW impact tested
WPS formed from these two PQRs FCAW /SAW
Qualification range shown on WPS - 16 mm (5/8") to 200 mm (8")
Maximum Deposited Weld Metal shown on WPS: FCAW 200 mm / SAW 200 mm

1  What is the thickness qualification range for impact tested material as per ASME VIII ?
2  Are the impacts from the combination of 2 processes from 2 different PQRs acceptable or should impacts be done on the FCAW/SAW WPS combination ?
3  Backing was provided by GTAW and SMAW in the original PQRs but on the WPS it states "Note 1 ; No backing for first layer, weld backing for second layer in single welded groove." How do they put a root run in with FCAW ? There are nine pictures of joint configurations on the WPS and eight of them are open root ?

Any help greatly appreciated,
Regards,
Shane
Parent - - By js55 (*****) Date 03-19-2009 13:40
Shane,
You won't find thickness limitations in ASME Section VIII for impacts as you are used to in B31.3. You do however need to hold to the 1/16" distance from the surface, verify your MDMT and the thicknesses involved, verify this against the curves, and make sure you have all processes represented in the impact test specimens ( a common mistake).
I get you more info when I have a little more time.
Imapact testing in Section VIII is not too bad, determining if you have to do it can be a little more complicated.
Parent - By js55 (*****) Date 03-20-2009 13:22
The greatest difficulty with Section VIII on impacts (IMO) is determining if you have to do them (and some dissimilar scenarios get a little muddy). At least for me. However, doing them is very basic.
Same size specimens, reference to A-370, MDMT temp for testing temp. If your doing carbon everything is based on UCS 66 and Section UCS 67. UG-84 for the general stuff.
Once you get into it and you have specific questions let me know.
Also, pay attention to UG-84(i). Production test plates are a foreign idea to pressure piping experience.
Parent - - By Nanjing Date 03-20-2009 14:21 Edited 03-20-2009 14:25
Shane, I think you can combine these procedures (without seeing them remember or the vessel design condition etc) to qualify welding material from 16mm to 98mm.. ASME VIII references you back to QW 250 of ASME IX (UG-84(h)(4). I think whoever wrote the WPS has interpreted that you can combine the the thickness T of each procedure along with 403.7 to give a maximum thickness qualified of 8". This is not the case. Each procedure is limited to 2T. 403.7 only gives further restrictions on T for base materials above 8". Both procedures at this thickness should also have cap and root impacts as well as HAZ. I do not know how they weld an open root with the flux cored wire quoted. Normal to have SMAW backing or a ceramic tile otherwise the wire will just go shooting through any gap. Who built the vessel? Vijay?

Regards

NKG
Parent - - By js55 (*****) Date 03-20-2009 14:56
Maybe I'm misreading this. Where is the 2T coming from?
Parent - - By Nanjing Date 03-20-2009 15:35
No you did not misread it I did! QW 451.1 does allow this for the thickness qualified. Apologies to all.
Parent - - By Nanjing Date 03-21-2009 13:01
This has been bugging me. How can you jump from 2" thick to 8" thick when low temperatures are involved?
Parent - - By Shane Feder (****) Date 03-22-2009 20:34
Nanjing,
My concern is mainly, if you do impact tests on a GTAW/FCAW coupon and impact tests on an SMAW/SAW coupon how can those results have any relevance to a FCAW/SAW WPS that is written by combining just 2 of the processes ?
Surely impacts should be done on a FCAW/SAW coupon to confirm if the mechanical properties of that weld are acceptable?
Regards,
Shane
Parent - By Nanjing Date 03-23-2009 12:20
Don't quite see where you are coming from Shane. The FCAW will be impact tested on one procedure and the SAW on the other. Are you concerned about the fusion zone between the two?
Parent - By js55 (*****) Date 03-23-2009 17:06
"Surely impacts should be done on a FCAW/SAW coupon to confirm if the mechanical properties of that weld are acceptable?"
There is no theoretical or practical basis for this assumption.
Parent - - By js55 (*****) Date 03-23-2009 16:22 Edited 03-23-2009 16:25
The assumption is, that once you get into the triaxial stress range (~5/8", as exemplified in the thickness requirements under ASME Section IX-and the fact that Section VIII and B31.3 emphasize the specimen being within 1/16" from the surface-Section III is a little different going with the 1/4 T location) the impact properties will not vary to any significant degree. B31.3 has chosen to take a more stringent approach with greater thicknesses, Section VIII has not (although all welding processes must be represented.
Parent - - By Shane Feder (****) Date 03-23-2009 20:11
Sorry guys, my apologies.
I am showing my naivety towards impact testing.
I was under the (mistaken) impression that a WPS with higher heat input / higher deposition rates (FCAW/SAW) would have significantly different impact test results than say a GTAW/FCAW coupon.
How do you tell if an impact test is acceptable ?
The two PQRs I have noted above were tested at -35 degrees C
There are seven locations ( 3 x WM - 4 x HAZ) with three readings at each location
The GTAW / FCAW procedure has 7 averages totalling 855 joules (min 33 max 165)
The SMAW/SAW procedure has 7 averages totalling 979 joules (min 114 max 170)

Do these results sound OK ?
Regards,
Shane
Parent - By js55 (*****) Date 03-23-2009 20:22
Shane,
You need to determine what the min impact energy required is. If the results comply with the min required you're good to go.
Establish the max heat input for each process. That is your max on the WPS.
As for HAZ's match them with the weld process locations and use the results in the same manner you used the result of the weld test. In other words, you should have HAZ data that is the same depth as your weld process, for example GTAW, the same depth will be your GTAW HAZ.
Parent - - By Nanjing Date 03-24-2009 14:31
Shane, I do not think you are off the mark with your statement about higher heat input/higher deposition rate as long as you are considering similar thicknesses generally.

I have a few questions;

What is the material specifications & grades, properties and consumables used (including manufacturer)
What is the actual thickness and has it been post weld heat treated (can't remember all the previous details).
Is the design code ASME VIII or EN 13445 (or God forbid some AS/NZ standard that doubles up for shearing sheep)?
Any additional owner requirements?

With impact results the norm is that, for each of the three values at each location, you determine the average and note the minimum and check to see if these meets the requirements of the standard/code. To the American standards, and I am sure I will be corrected if I am wrong, you must meet the base material requirement at the MMDT (or if not specified in the standard the owner must give the requirement). Impacts are taken from various locations, eg cap WM and HAZ (+2mm +5mm), root WM & HAZ depending on which standard/code you are working to but I think I am safe in saying you do not add them all up and take an average overall(as I have think you have done), never seen that.

NKG
Parent - - By Shane Feder (****) Date 03-24-2009 19:38
Hi Mr B,
ASME VIII Div 1
PQR GTAW / FCAW
SA 516 Gr 60 to SA 516 Gr 70
49 mm to 49 mm
ER70S-G (TGS-IN) KOBE
E71T-12JC (Formula XL 550) Hobart
PWHT

PQR SMAW / SAW
SA 516 Gr 60 to SA 516 Gr 70
49 mm to 49 mm
E7016-G (LC-300NS) CHOSUN
F7P8 / EH12K (Union S3Si / UV418TT) Thyssen
PWHT

Design temperature -35 degrees C to + 50 degrees C

The readings I can't understand are the GTAW / FCAW
There is 5 mm of GTAW and 44 mm of FCAW yet the result of WM (Root) is 46J and WM (Midway) is 33J
Is that not very low for FCAW ?

On another note, Tropical Cyclone Jasper has hit New Caledonia last night. They are looking at evacuating us from site today. Doesn't look promising for my demobilisation flight tomorrow.
As long as I am stuck in Noumea and not on site I will be happy.
All the best,
Shane
Parent - - By js55 (*****) Date 03-24-2009 20:02
What was the test temp?
What is the MDMT required?
Take a look at the UCS 66 curves. Normalized SA516 is 2 curves lower (curve D) than as rolled.
Parent - - By Shane Feder (****) Date 03-24-2009 20:59
Hi js55,
Test temp -35 degrees C
MDMT -35 degrees

Packing my bags to get evacuated at the moment so will have a look at UCS 66 at a later date,
Regards,
Shane
Parent - By js55 (*****) Date 03-24-2009 21:20
Take care. Stay out of its way.
Up Topic Welding Industry / Technical Discussions / Impact tests to ASME VIII Div 1

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