charpy Impact failing in HAZ and Weld

Date 03-16-2013 04:19

We would need a lot more detail to provide you with a meaningful response.

What were the actual welding parameters, the volume of the individual weld beads (approx.), maximum interpass temperatures, minimum interpass temperatures, etc. Did you age the samples before testing?

Brand names of the filler meal and flux used can also affect the final outcome.

Best regards - Al

By Hojo

Date 03-19-2013 11:45

The welding parameters were as follows:
There were 4 passes of GTAW deposited with the first pass at 191A and 19.5V @ 73.4Kj/in heat input
The other 3 passed of GTAW were depostied at 250A and 21.5V @ 116.5Kj/in heat input
Preheat for the GTAW was ate 75°F with a maximum interpass temp. of 125°F reached.

There were 15 passes of SAW deposited as follows:
1st pass was at 475A and 28V with heat input at 46.9Kj/in
All the rest of the passes were at 500A and 29.9V with heat input at 60.0Kj/in.

The GTAW filler metal was Midalloy and the SAW filler wire and flux was from ESAB.
Not sure what you mean by Aging the samples as they were heat treated within a couple of days of the welding and the lab testing took place about a week later.
We have been using these filler metals and the flux and performed Impact testing before without these kind of problems before.
We have also performed some hardness tests on cross sections of the welded samples that were removed before PWHT and the Vickers hardness numbers are all at 200HV or less in the Weld, HAZ and the base metal.

Thanks for your help.

By MMyers

Date 03-19-2013 13:47

More questions:

What is the test temperature?
Have you had success with these materials and heat treat cycle passing impact testing at this or lower temperatures before?

By Hojo

Date 03-19-2013 13:51

The Impact testing temperatures were at -55°F and we have passed charpy testing at this temperature before with these filler metals and base metals both with and without PWHT.

Tkx

By 99205

Date 03-19-2013 15:42

Have you checked you shielding gas for contamination?

By js55

Date 03-19-2013 20:05

One thing that jumps out at me is 115kj/in for GTAW. Thats cookin it man. There ain't no normalized microstructure left after that.

By js55

Date 03-19-2013 20:07

Another thing that jumps out at me is 21.V for GTAW?
YOu running machine GTAW?

By js55

Date 03-19-2013 20:11

Another thing to consider, you said you're runnin double bevels which means steep bevel angle,as opposed tosay a compound bevel. Even though you failed the HAZ you can't get the specimen entirely on the HAZ. Fracture initiation may have been elsewhere.

By js55

Date 03-19-2013 20:12

Also, 2o0HV seems a bit high for GTAW at 115kj/in.

By MMyers

Date 03-20-2013 14:06

I wonder if that's the machine voltage at the terminals, not the voltage at the torch.

By MMyers

Date 03-20-2013 14:09

Ok, it sounds like you either have a welding procedure problem, or a testing controls problem. I'd start grilling the test lab to make sure their ducks are in a row. While they're getting info together, look at all the material and welding details on your side to see if there are any details that stick out from the previously completed test plates.

By ozniek

Date 04-12-2013 08:45

Hi Hojo

Some of the heat inputs you have given, are very high. These values will certainly result in poor impact properties, as you will end up with a lot of grain growth. The longer the PWHT, the more the grain growth, so this will exacerbate an already bad situation.

If welded with lower heat inputs, you should relatively easily pass the impact tests. I am assuming that you are just using the standard carbon steel filler metals with a neutral SAW flux.

As stated by some of the other people, your voltage for the GTAW look suspiciously high. You should make sure that you are measuring the voltage as close to the arc as possible, as there are significant voltage drops accross long welding leads.

Regards
Ozniek

By pgoswami (*)

Date 04-12-2013 19:36

Hi Hojo,

Could you take a look at the following ESAB link and say what wire & flux combination was used for SAW.

Also how good was the impact test report for base metal: test temperature vs the impact values.
How good was the impact test report for weld metal:- test temperature vs the impact values.
Where are the failures:- Weld or HAZ.
GTAW heat input look slightly high , but SAW heat input does not look that high.

I would think all these info are pertinent for the root cause analysis. Many a times incorrect wire flux combination could be be the aggrevating factor.

Thanks

PG

http://www.esab.com/de/de/support/upload/XA00136020-Submerged-Arc-welding-handbook.pdf

By varun Date 10-11-2017 07:39

We are welding SA-516 Gr70 to 516 Gr70, 8 MM thick plates with single bevels. We have a 8 MM thick deposit of GTAW (ER70S-2) in the root with the balance of bevels filled.
Heat input for the GTAW was 1.85 KJ/MM to 2.35 KJ/MM . The interpass temperature was 130 – 150°C.
The Charpy inpact numbers all fail in the HAZ (values are HAZ 1,2 & 3 – 210,206,214 & Energy Absorbed1,2 & 3 – 8,10,18Joules & Average joules Actual-,12,Required- 12 Minimum),Test Temperature = -49°C ,MDMT = -39°C and two specimens even failed in the weld on the plate.
The plates were all purchased in the normalized & impact (-46°c) condition with the grain structure perpendicular to the weld.
Anyone care to comment?

Regard's

Varun Kumar

By Chrismatt34 Date 08-09-2018 20:42

Did you ever figure out the issue?
To me using a 70 series filler is not suffice for low temp Charpy testing. We usually go with a 80ni filler for those types of procedures. We are having failing charpys at the root fusion line only in 2.5 plate. CTOD requirements are very stringent.