Hit wrong button, Sorry guys!
As I was saying I need a good starting point on the particulars from electrode size, nozzle size, approx. gas flow rate etc.
I have welded some prototype pieces on a friends machine, also a SW 250, and I was using 1/8" Pure for electrode material as that is what he had, be it right or wrong. and the pieces seemed to come out alright. I know that just starting out I am picking the worst thing to learn on, but my buddy says that if I do the AL OK, other material are easy.
Any help is appreciated.
Thanks guys,
Regards,
Tom Marino in PA
tgmedin,
What is about Al that makes you think it's the "worst" thing out there?
Aluminum is a different material, as compared to carbon steel, or stainless, or HY-80, or copper-nickel, or Inconel,
or any of the different possible base metal configurations used in existence today. I don't think Aluminum even comes close to Titanium, as far as the shielding considerations are concerned.
I doubt if learning to weld Aluminum is going to make you a better welder than anyone else. True, it's got it's own particulars involved in successfully completing a weldment, but no more so than being a good carbon steel or stainless welder.
Each and every material composition has it's own particular procedures and requirements.
Dale Simonds
Just some typical parameters: (There are obviously other options.)
Use AC current with HF switched on. This makes the arc somewhat more stable. Use the pure Tungsten. You will see that it tends to melt and makes a "ball" on the end, this is what is supposed to happen. Remove as much of the surface oxide scale as possible, typically with a wire brush.
The material you are welding is very thin, and consequently will be rather difficult to weld without burning through. If your machine has pulse capability, then it may be adviseable to switch this on. Use a very low back-ground current to allow the material to re-solidify between pulses. As I sit here, I can not tell you exactly what current to use, but just experiment till you get it right.
Shielding gas flow rates is not hell of a critical, so the typical values used will suffice. (Around 10 - 20 litres/min)
Hope this helps
Niekie Jooste
tgm,
More specific info would help.
What type of joint, position, shielding gas, CJP or PJP, etc.?
You can also use many of the other electrodes such as 2% thoriated tungsten. Ball the tip with DC+ (at low current), then switch back to the AC.
Continuous high frequency.
If your machine has the pulsing options, the previous post is not a bad idea either.
Clean the material just prior to welding. Todays cleaning becomes tomorrows Al oxide.
I recommend using the smallest possible electrode size that will be used at the current range you will be welding with. Too large size of tungsten results in erratic arc starting and a "wandering" of the arc during welding. For that thickness I use a 3/32" tungsten.
Good Luck.
Your using very thin stuff so go with a 1/16 pure tungsten electrode. Your amps will differ as your position changes. Start with around 60-80amps, and if your going out of position reduce the amps by 10%-15%.
Use a Ar shielding gas with a flow rate of 15CFH or 20PSI. Try and get a consistent travel speed. If you find your burning through then go little faster. Try around 12"/minute as a starting point.
Again, without specific info, it's guess work at this point.
At 80 amps you will be near the upper limit for a 1/16" EWP electrode which may result in tungsten splitting and the possibility of contamination in the form of inclusions in the weld. The wave balance may also reduce the maximum current carrying capacity of the electrode depending on the polarity ratio (percentage of electrode + vs electrode -). As previously stated, the gas or gas mixture will make a substantial difference as well including flow rate, current, etc. If a helium rich mix is used then the flow rate will increase due to the lighter gas (He is approx. 10 times lighter in weight than Ar).
15 cfh is the flow rate of the gas (a good starting point by the way) depending on the gas or gas mixture and depending on the nozzle size.
20 psi is the pressure for XX flow rate, these are two different values.
MORE INFO if this weld is important to you.
Example:
A PJP corner joint with a 1/16" root opening welded in the overhead position will require much less current than a CJP butt joint with 0 root opening in the flat position.
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