B31.3 impact test for base materil

[OZWelder]

Hello all.

I have just stared as welding QA. I have been working as Welder for 11 years ans my first job is to develop PQR for our client. welding must be qualified to ASME IX construction code is B31.3.

client specification is impact testing must be conducted at -60deg C
all material is A790 UNS31803 22%Cr DSS ranging is wall thickness from 3.8mm to 30mm
(impact testing to be in weld metal FL+2)

my question is on the material certificate I noticed that the pipe I have perched to weld coupons for testing has had CVN at -50deg C and the 25mm plate I have perched for weld coupons has only got CVN tested at -46deg C.

1. Will I have to re-test base material to -60. So after welding coupons have the lab do CVN for weld metal, FL+2, FL+5 and base metal?
{b}2. how to I work out the minimum impact values for -60 CVN testing. The client first told me that CVN testing would be -50deg C and i think about 50J/42J (around there) now how do I work out what is minimum impact value in Jules for new temp of -60deg C?{/b}

if I have ISO drawing with design temp rang of -46 to +80 and hydro test pressure of 35000 Kpa using ASME B31.3 how do I work out CVN test temperature and single/average Jules required?

I thank you all for you help in advance...

 

[weldstan]

First you need to define the weld filler metal. B31.3 defines the minimum absorbed energy required for the weld metal or the minimum lateral expansion based on the weld metal chemistry (P No. or F No.) You do not define the absorbed energy required but your client or owner may do so in their specifications.

 

[EdStainless]

What is driving the impact testing? Is it actually the service temp of is it A923 requirements?
A923 is a check on the microstructure and requires testing at -40.
It requires 54J min.

I presume that the weld filler is 2209, SFA5.9, A8, F6 (or maybe that alloy in another form).

If your actual service temp reaches -56C then you seriously need to test all material (base, HAZ, and welds) at -60C.
This alloy is generally not used below -40 because it has a DBT. (well the ferrite phase does)

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P.E. Metallurgy, consulting work welcomed

 

[david339933]

323.2.2
Table A-1
Table 323.2.2
Table 323.3.1
323.3.5
Table 323.3.5

 

[1503-44]

And, according to Bob, Min is 2/3 of average

https://www.inspection-for-industry.com/asme-impact-test-requirement.html

 

[OZWelder]

hay thank you all for the responce.

first the filler wire I have proposed to use is Exaton(ESAB) 2209LSi 22.8.3LSi the manufacture say at -50C this wire can achieve 145J.

The gas I want to use for the back purge and the shielding is welding grade argon with 2% nitrogen, for both backing and shielding. This it because nitrogen is a good austenite enhancer and I want to try and keep the ferrite level low, to try and have good ductility and corrosion. The filler wire 22.8.3LSi also has Ni of about 9% so this is good austenite enhancer as well.

The client is the one driving the impact testing at -60C. From the ISO pipe drawing I have got the minimum design temperatures is -48C, so not sure why -50C is not good enough for impact testing. The client also will not tell my what is the acceptable impact value. Thy say just get it testing and they will look at the reports and tell me if it good enough compared to their base material reports. But the pipe I have brought for the PQR's has only been tested to -50C and and plate (as I could not buy pipe at 25.4mm wall thickness, I would have to wait 9 weeks to get that so went for 25mm plate in the 3G up position will still cove all position in WPS) the pipe for the actual project will be supplied by the client, so that is their responsibility to get me pipe that is good at -60C. I just really want my PQR's to pass hehe.

There will be many many other tests preformed on the PQR's including ASTM A923 method C at +22degC (instead of G48) I would of like to just do G48 but again the client has said no.

I have look at the 323.2.2, table A-1 and that. As far as I understand how to read them tables I can only see that 22% DSS UNS31803 information for -50C. I was unsure how to determine the impact values of both the individual/average joules or will I find this in a ASTM standard? Some of my specimen will be sub-size just to make it a bit more complex with a wall thickness of 5.8mm so the specimen size after machining will most likely be around 5mm. But I am prety confident that I will be able to get a notch size of at least 80% with the 5.8mm wall thickness pipe.

I am not sure why if you need such low temperature impacts why the client is not using an Austenitc stainless steel instead of DSS but I am no design engineer that for sure so not my place to question them.

 

[OZWelder]

Sorry

P No = 10H group 1
A No = 8
f No = 6

 

[weldstan]

B31.3 minimum absorbed energy values have been met at -60 C in the deposited weld metal using the proposed weld filler metals and shielding gasses with the GTAW process. I forget the actual absorbed energy that we obtaied but, as I recall, they were in excess of 50 ft-lbs.

 

[OZWelder]

Thanks all for the response’s.
I am quite confident we will meet the impact values but I will have to go through b31.3 to find the min and average values required. If not I will ring the mechanical testing lab and ask them. This is more for my own education, I want to learn to be able to find all the answers to code related questions my self.

Also if I am qualifying to ASME IX 2020 and B31.3 2020. Am I correct in saying that the thickness range qualified is now the same for both codes and not t to t+6 for B31.3 and t to t2 b31.3. Now they are both as per ASME IX. Do my thickness ranges qualified for both section IX and B31.3 will be- 1/2t to 2t for less then 6mm and t to 2t for thickness up to 38mm and over 38mm 16mm to 2t??

 

[EdStainless]

QZW, I just wrote a WPS and qualified a pair of PQRs (GTAW & GMAW) for 2205 pipe.
There are a bunch of details to watch out for.
Make sure to use 2% N2 in the weld gas (some people back with it also).
Good backing and purge is critical.
Very low interpass temp limits.
Actually measuring the phase balance.
Keeping the heat input up, low is more risky than high with this alloy.
And a few others.

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P.E. Metallurgy, consulting work welcomed

 

[OZWelder]

tHANKS eDsTAINLESS

I have submitted my pWPS with a 2%N gas mix on both the backing and the torch gas. will start running the PQR tomorrow so I hope I have all bases coved. I am now just trying to determine what the min Joules are according to ASME B31.3.

thanks so much for every one input on this thread..
Alot of smart people out there ...

 

[SJones]

Your client might have been influenced by the Rolled Alloys approach to super duplex quality Charpy energy requirements discussed in NACE Corrosion 2012, Paper 1096. ISO 17781 has two levels of quality requirements: QL I and QL II. The Charpy acceptance criteria for welds in the as welded condition are:

QL I - 50J average 40J individual
QL II - 35 J average 27 J individual

The nominal test temperature is -46 deg C, but the standard advises that lower test temperatures can be "considered acceptable" (whatever that means)

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[OZWelder]

Cheers SJones,
I will have to hunt that paper down and add it to my ever growing list of material I must read.

For some reason I think the client has got confused with degree F and degree C..

As when I read table A-1 the minimum temperature for USN31803 is -51C but if you convert that to deg F it is -60!!

But they seam pretty sure they want impact testing done at -60 C…

No one I have talked to yet (except for one post in this thread) has had to do impact testing on welded pipe 22%Cr duplex at-60c which is -76F ??

If any one has had to achieve impact of 40/50Jos or 0.38mm expansion at -60 Celsius please let me know anything that might trip me up.

Like did you have to get mill order duplex pipe that was tested at -60 as I can only buy pipe tested at -50C

Cheers

 

[EdStainless]

OZW,
I have never tested 2205 below -50F.
The set that I did recently was tested at -40C/F. (actually -41C)
All samples (weld and HAZ) were in the range of 95-116J for half sized samples.
The Lat Exp was 0.075"-0.090" (1.9-2.3mm).
These are good values, but not unusual for high quality material.
From the standpoint of metallurgical integrity we use 54J as a threshold.
This is to validate that the microstructure is substantially free from harmful secondary phases.


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P.E. Metallurgy, consulting work welcomed