Aluminum 5083-H116 Welding With 5356 Wire Cannot Pass Tensile Requirement!

[Victor Wilson]

Hello all,

I am a mechanical engineer by trade. About 6 months ago our company's welding engineer got into an accident and I have been volun-told to head our welding department in her absence. I have been doing quite well up until we got a job for a defense contractor about 6 months ago. I have tried pretty much everything to get this passed. We are qualifying this to the AWS D1.2 standard and have failed our tensile requirement of 40ksi (welded) with every method we have tried. I need some insight from anyone who may have encountered this or has much experience with aluminum welding.

I have tried:
- using a chill bar
- Full MIG
- TIG Root with a MIG fill
- CJP using a backgouging technique and LPI'ing the backgouge before re-filling
- Pre-heating the plates in an oven (around 200 fahrenheit, much below the annealing temp)
- Pulsed MIG with a trim of 1.01
- Tried 70% Ar 30% He gas
- 100% Argon gas

There is likely more we have tried that I have forgotten but suffice to say, we cannot seem to lick this thing. We clean between every pass with a stainless steel brush, we have water cooled guns, I really am not sure what else can be done. We are welding in a separate cell from our carbon steel welding cells. Our problem I believe is a mixture of porosity (found by macro-etching our specimens) and also the heat input which is why we tried pulsed methods. The heat input is also why we chose to use 100% Argon rather than the helium mix. Any help you guys can provide would be appreciated. Thank you!

[iongar]

try using 5556, will have much better results than 5356 if you are allowed. 5556 is used for groove welds and typically meets 45kpsi in groove weld structural applications.

[A_DAB_will_do]

More details about the joint geometry and the application please. How thick is the material and what position is the test plate being welded(flat, vertical,etc). Pictures of a representative sample and the macroetch might also be helpful, if you can share them publicly.

[Weldeng13]

Agree with the 5556 or try 5183 which is a bit weaker.
Assuming you don't have leaks/drafts, proper cleaning is critical to helping prevent porosity, suggest degreasing, oxide removal, then a light cleaner like acetone.
Low interpass temps are better.

Peter

[Victor Wilson]

Awesome, I will give it a try! Why the specificity to grooves? Has to do with the alloying elements?

[Victor Wilson]

Unfortunately I can't share any drawings or anything publically but the groove details are outlined:

- 53 Degree single bevel
- 1/16" root face
- 5/8" thickness
- Plate Test

The application from what we believe is for a floor plate on an armoured vehicle. They require a tensile of 40ksi minimum and also require 2 side bends.

[shovelon]

Have you passed your guided bend tests?

I agree with the 5556 filler. However an excess of porosity tells me too much base metal dilution, bad gas coverage, or a combination of both. From what you describe the failure is in the weld nugget or fusion zone?

Are you pushing the weld as to lift the smut ahead of the weld?

[HT2-4956]

Just happened to be reviewing this chart for another application.

http://www.maxal.com/files/QuickSite...tion_Chart.pdf

Looks like what "iongar" said in post #2 about 5556 being the preferred filler might be the solution to this problem. According to this 5356 is not up to the task.

[Victor Wilson]

We have not been able to pass the bend tests, although instead of a guided bend tester we use the plug technique. The heat seems to affect tensile and ductility equally. We have checked our gas, soaped all the fittings to check for leaks that may draw in contaminants. The failure is in the heat affected zone and the weld itself, there is porosity in the welds itself but sometimes during tensile the failure occurs in the heat affected zone not the weld. We are pushing the weld bead.

[Victor Wilson]

Have you passed your guided bend tests?

I agree with the 5556 filler. However an excess of porosity tells me too much base metal dilution, bad gas coverage, or a combination of both. From what you describe the failure is in the weld nugget or fusion zone?

Are you pushing the weld as to lift the smut ahead of the weld?

We have not been able to pass the bend tests, although instead of a guided bend tester we use the plug technique. The heat seems to affect tensile and ductility equally. We have checked our gas, soaped all the fittings to check for leaks that may draw in contaminants. The failure is in the heat affected zone and the weld itself, there is porosity in the welds itself but sometimes during tensile the failure occurs in the heat affected zone not the weld. We are pushing the weld bead.

[HT2-4956]

We have not been able to pass the bend tests, although instead of a guided bend tester we use the plug technique. The heat seems to affect tensile and ductility equally. We have checked our gas, soaped all the fittings to check for leaks that may draw in contaminants. The failure is in the heat affected zone and the weld itself, there is porosity in the welds itself but sometimes during tensile the failure occurs in the heat affected zone not the weld. We are pushing the weld bead.

Victor,

Based on a quick read of this research article... https://app.aws.org/wj/supplement/WJ_1975_03_s95.pdf

Have you checked the "dew point" of your shielding gas? And what about the possibility of installing some kind of dessicant dryer in your shielding gas line to help insure it's as low as possible.

Have you taken a close look at your filler wire to make sure it's good and clean and not a source of contamination that's causing the porosity. In the past I've run into aluminum wire that had enough residual lubricant on it from the drawing process that it caused problems. As a quick check I'd suggest taking a clean white piece of cotton cloth and pulling some wire thru it to see if it's leaving any residue.

[HT2-4956]

http://www.shipjournal.co/index.php/...le/view/68/246

[HT2-4956]

Victor,

Some of the answers to your problems are probably in this.

http://www.maxal.com/files/quicksite...g_6-11_doc.pdf

[A_DAB_will_do]

Stupid question, since you have failures in the HAZ, have you ruled out a problem with the base metal as a contributing factor? Do the material certifications show sufficient strength to meet the application, and are you cutting the test plates with the proper orrientation to the rolling direction of the base material. Some information I grabbed from google relative to the H116 temper designation, that I was unfamiliar with:

http://www.aluminum.org/sites/defaul...porttheMar.pdf

“H116 - Applies to products manufactured from alloys in the 5xxx series,
for which the magnesium content is 3% nominal or more. Products are
normally strain hardened at the last operation to specified stable tensile
property limits and meet specified levels of corrosion resistance in
accelerated type corrosion tests. They are suitable for continuous service
at temperatures no greater than 150°F (66°C). Corrosion tests include
inter-granular and exfoliation;”

Since the material is cold worked, the HAZ will be annealed by the welding process to some extent. If there is any chance the base metal properties aren't right or your cutting plates such that the weld is parallel to the rolling direction of the base metal, that might be playing a role in your issues.

I agree with Shovelon that porosity implies another separate issue that could be gas contamination, surface contamination, another, as yet unknown problem.

[A_DAB_will_do]

If changes to base metal are an option, maybe you guys should be looking at 5083-H321. H321 is strain hardened and then aged for better ductility. Otherwise it's the same alloy.

https://www.lightmetalage.com/PDFs/L...mpersPartI.pdf


Just tossing out some additional ideas.

[HT2-4956]

And spit ball'n further on from what DAB has said above about the weld annealing the HAZ.....

Maybe the answer lies in reducing the heat input. For instance instead of 2 (or 3) heavier passes to complete the joint less annealing of the HAZ could be achieved by using 3 (or 4) smaller passes with a lower interpass temperature.

Concerning the porosity issue.....when back gouging is being done, what's it being done with? I can see grinding leaving some embedded particles that would contribute to porosity issues.

[Victor Wilson]

Victor,

Based on a quick read of this research article... https://app.aws.org/wj/supplement/WJ_1975_03_s95.pdf

Have you checked the "dew point" of your shielding gas? And what about the possibility of installing some kind of dessicant dryer in your shielding gas line to help insure it's as low as possible.

Have you taken a close look at your filler wire to make sure it's good and clean and not a source of contamination that's causing the porosity. In the past I've run into aluminum wire that had enough residual lubricant on it from the drawing process that it caused problems. As a quick check I'd suggest taking a clean white piece of cotton cloth and pulling some wire thru it to see if it's leaving any residue.

It's funny you source that, I read the same study this morning! We are using a welder that has a 2 foot line attached to it from a bottle of argon so I thought about installing a dryer of some sort but when i looked into it, its only necessary for plant systems as condensation can collect in long lines. For argument's sake though, how do I test dew point?

We just got a spool of 5556 in this morning so I will test it for residue before we run today's test and let you know!

[Victor Wilson]

http://www.shipjournal.co/index.php/...le/view/68/246

Also read this article a few weeks back which is why we gave the pulsed MIG process a shot.

[Victor Wilson]

Stupid question, since you have failures in the HAZ, have you ruled out a problem with the base metal as a contributing factor? Do the material certifications show sufficient strength to meet the application, and are you cutting the test plates with the proper orrientation to the rolling direction of the base material. Some information I grabbed from google relative to the H116 temper designation, that I was unfamiliar with:

http://www.aluminum.org/sites/defaul...porttheMar.pdf

“H116 - Applies to products manufactured from alloys in the 5xxx series,
for which the magnesium content is 3% nominal or more. Products are
normally strain hardened at the last operation to specified stable tensile
property limits and meet specified levels of corrosion resistance in
accelerated type corrosion tests. They are suitable for continuous service
at temperatures no greater than 150°F (66°C). Corrosion tests include
inter-granular and exfoliation;”

Since the material is cold worked, the HAZ will be annealed by the welding process to some extent. If there is any chance the base metal properties aren't right or your cutting plates such that the weld is parallel to the rolling direction of the base metal, that might be playing a role in your issues.

I agree with Shovelon that porosity implies another separate issue that could be gas contamination, surface contamination, another, as yet unknown problem.

We have a material mill cert, the material had to be ordered from Florida (I am in Canada). The material cert showed tested values of 44-47 ksi. So we should be ok, its just about mitigating the amount of tensile we lose so it doesn't drop below that 40ksi. But yeah the temper indicates strain hardening so we can't heat treat it and as soon as we strike an arc we are losing tensile strength and ductility. That paired with the 5/8" thickness makes it crazy as right now it is requiring 12 passes to fill the test plate groove. We cut all the plates in the rolling direction out of a 5' x 10' sheet using a waterjet. We did have a leak in our gun's water cooling mechanism which made the material pretty much unweldable but that has been fixed and yet the porosity is still there.

[Victor Wilson]

If changes to base metal are an option, maybe you guys should be looking at 5083-H321. H321 is strain hardened and then aged for better ductility. Otherwise it's the same alloy.

https://www.lightmetalage.com/PDFs/L...mpersPartI.pdf


Just tossing out some additional ideas.

Also yeah we tried to pitch the idea of just making the part out of solid aluminum and machining it rather than welding it but they wouldn't go for it. Same with material type/temper but no such luck. The closest we have gotten a test was 39,400 psi out of the required 40ksi. And we only hit that once. Averaging about 35ksi.

[A_DAB_will_do]

It's funny you source that, I read the same study this morning! We are using a welder that has a 2 foot line attached to it from a bottle of argon so I thought about installing a dryer of some sort but when i looked into it, its only necessary for plant systems as condensation can collect in long lines. For argument's sake though, how do I test dew point?

We just got a spool of 5556 in this morning so I will test it for residue before we run today's test and let you know!

Contact your welding gas supplier and ask them to certify that the bottle gas you're receiving has a dew point below -80°F(I'm guessing that's the right temp, it should be something close to that). If your operation runs off of a microbulk system, try using a small bottle near the machine. double check your gas hoses too. No using cheap compressed air line for shielding gas hose or some other substitute for the hose made from an inert polymer material.

[Weldeng13]

Reducing interpass temperatures and heat input will help you on tensiles

If you are ordering gas to a5.32 and receiving a cert for each batch shouldn't have a problem with bad gas.

What are your cleaning steps?


Sent from my iPhone using Tapatalk

[HT2-4956]

It's funny you source that, I read the same study this morning! We are using a welder that has a 2 foot line attached to it from a bottle of argon so I thought about installing a dryer of some sort but when i looked into it, its only necessary for plant systems as condensation can collect in long lines. For argument's sake though, how do I test dew point?

We just got a spool of 5556 in this morning so I will test it for residue before we run today's test and let you know!

Victor,

It's not just that it could be picking moisture up from condensation in long lines but that the Argon it's self could have been bottled with too much moisture content in it. When I was stationed aboard a nuclear submarine tender years (and years) a go we had a dew point meter we ran a sample from each bottle thru before using that bottle for any welding. It was a fairly good size piece of laboratory equipment but I'm sure by now they've probably got it down to a hand held size electronic device. Just search for "dew point metering of compressed welding gases".

https://pubs.aws.org/Download_PDFS/a...32m-1997PV.pdf

[Victor Wilson]

Reducing interpass temperatures and heat input will help you on tensiles

If you are ordering gas to a5.32 and receiving a cert for each batch shouldn't have a problem with bad gas.

What are your cleaning steps?


Sent from my iPhone using Tapatalk

We use both a stainless steel wire brush and a stainless steel wire disk for cleaning between every pass. Stayed away from solvents as we didn't want any possibility of that being our issue.

[Victor Wilson]

Victor,

It's not just that it could be picking moisture up from condensation in long lines but that the Argon it's self could have been bottled with too much moisture content in it. When I was stationed aboard a nuclear submarine tender years (and years) a go we had a dew point meter we ran a sample from each bottle thru before using that bottle for any welding. It was a fairly good size piece of laboratory equipment but I'm sure by now they've probably got it down to a hand held size electronic device. Just search for "dew point metering of compressed welding gases".

https://pubs.aws.org/Download_PDFS/a...32m-1997PV.pdf

I just looked up a dew point meter, kinda pricey as we are a smaller company, if we knew for sure this was an issue I might be able to convince my boss on it but not sure he would exactly spring at the opportunity without some serious evidence.