Looking for general information about welding of 5083 Aluminium 3

[kingnero]

As the title says, could somebody refer me to some literature to start with?
I'm preparing for a project where heavy sections of 5083 will be MIG welded, and I have experience from previous projects (welding 6xxx alloys) that suffered from rather severe porosity.
I'm trying to get to know the quircks of welding 5083 in advance, in order not to loosing too much time when starting off, unlike previous times...

Thanks in advance!

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You will find 5083 less difficult than 60xx alloys. One of the standard wire grades is ER5356, which has reasonable strength and therefore feeds fairly well (an important consideration with Al). Purchase wire only from a premium maker, such as Alcotec.
We used a lot (75%) of helium in our shield gas mix. I always considered this an expensive way to mitigate inadequate base metal cleanliness. Use 100% argon for GTAW - with AC or square wave power source.
Cleanliness is a major issue for aluminum. If you try to fab Al in a carbon steel shop you can expect grief. Special preparation tools and techniques are essential.
Lincoln and Alcotec offer good fabrication guides; just google them.

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

 

[3DDave]

See this article -

https://app.aws.org/forum/topic_show.pl?tid=5590

 

[kingnero]

@ ironic metallurgist,
5356 has indeed been mentioned as the filler that will be used.
I hadn't heard about alcotec (with me being in Europe), however a quick search revealed it's part of the ESAB group, which is very well known here. I'll get there without problems, I've got some valuable contacts @ esab.
Thx!

@ 3DDave, thanks for the link.
It adresses porosity in 6061 aluminium, been there, done that (lost some hair over it, and the remainder changed to a lighter shade of grey)

I do have an additional question, that hasn't been answered so far: if you encounter porosity in aluminium (I'm talking 60xx in particular, however I don't necessarily want to limit my question to this alloy), first go-to is cleanliness. If all surfaces are clean, and there are no (external) contaminants, could the porosity originate from bad base material or filler wire (or both) ? If so, how to determine the exact root cause? SEM of a gas pore? Other?

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[gtaw]

If you are experiencing porosity in aluminum there is a 99% chance there is a source of hydrogen. Consider the following:
1) compressed air: it is used to power many tools used in the shop. If the welders are using air tools to prepare or clean the weld, they exhaust port should be toward the back end of the tool and use a 3 ft long tail hose to get the exhaust away from the work.
2) gloves: they should be worn when handling the material and they should be clean. Oils of any kind are a source of hydrogen. The oils in your skin keep your skin soft and flexible. Handling material, including filler metal with bare hands is like slathering oil on the material.
3) cleaning: the base metal and the tooling used to prepare or secure the material must be cleaned and free of oils, grease, and moisture. I typically use acetone to preclean aluminum and follow that with 90% isopropyl alcohol.
4) wire brushes, cutting tools (rotary files, burr bits, etc.), etc. need to be cleaned before use and during use. I soak the tools in isopropyl alcohol. Periodic cleaning during use is important. Wear gloves!
5) do not dry or blow chips and filings away using shop air. The air comes from an oil lubricated compressor.
6) oxides: 90% of the maximum oxide layer forms in the first 24 hours of exposure. Cleaning parts today and welding them tomorrow is a waste of time. Clean the parts immediately before welding. Hydroxide films contain hydrogen. The films must be removed.
7) machined or sheared edges should be draw filed to remove oxides from the roughened surfaces. Clean the file with alcohol before using it and while using it.

Best regards - Al

 

[kingnero]

Thx GTAW.

However, let's say, all of the above precautions have been adressed (even degreasing the files and wire brushes), and filler material was continuously cleaned using a rag with isopropyl alcohol wrapped around the wire and held with a bull clip inside the wire feeder.

Shielding gas was checked for moisture content/dew point.


Is it possible that there is porosity, originating from either base material, filler material, some sort of chemical reaction between both, or something else?

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[gtaw]

Consider the wipes you are using; cotton, synthetic,or paper? All of them are hydrocarbon based. The lint adhering to the filler metal or the base metal is a source of hydrogen.

I didn't mention it in my last post, but one could break open an area containing the porosity. If the interior surfaces of the pore holes are silvery, hydrogen is most likely the problem. If the porosity is discolored, shielding gas or surface contamination could be the issue. Hoses, connections, etc. need to be checked for leaks. If the hoses are old, they can have small leaks that could aspirate air into the system.

Check the filler metal to ensure the surface is clean and free of drawing lubricants. Reputable suppliers put their filler metals through a cleaning process to remove the lubricants. Some suppliers "scrape" the surface of the filler metal before packaging to ensure it is clean.

Make sure the filler metals are stored properly. They must be kept clean. Store the filler metals in a closed cabinet and place the unused and partially used spooled filler metal in the plastic bag and then back into the cardboard container to keep it clean. Rods should be stored in a plastic sleeve to keep it clean. Storing the filler metals in the welding booth, on the wire feeder,or in open cabinets is an invitation to contamination. I cannot tell you how many times I see spools left on the wire feeder in the open, uncovered for days at a time. Considering the grinding and if working adjacent to a machining center, the oily mists in the air, it isn't that difficult to see how the filler metals get contaminated.

Keeping a spool of filler metal covered while it is mounted on a wire feeder isn't that difficult. I use the same cardboard container it was shipped in. I cut a slot in the side of the box so it can be slipped over the spool. Presto! Instant spool cover and it free!

I do not allow more than one type of filler metal to be in the welding booth. Stored filler metals in opened containers exposes it to the shop environment; contaminated air containing oily mists and dust. Also, multiple filler metal types (classifications) stored in the welding booth increases the potential for the inadvertent use of the wrong filler metal.

I was in one shop teaching the welders to weld pipe using GMAW when I spied the helper actually greasing the "lubricator" on the wire feeder. That explained the black grimy goo built up on the guides and liners. The filler metals were stacked on the work bench where they serviced hydraulic pump, cylinders, and hoses. Can you say "oil contamination"? When I pointed out the issue, the supervisor moved the filler metals. Several days later one of the welders said, "You're not going to like this. Don't ever tell the boss I was the one to show you this."

The filler metals were moved to an outside open storage shed. In short order the containers and open boxes where covered with bird droppings. You can't cure stupid.

Best regards - Al

 

[kingnero]

Thanks for the detailed information! I will take all of your points into consideration.

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