Preheating of aluminum using oxyfuel torch 3

[waqasmalik]

Hi all, please find the attached page. Its a snapshot from welding metallurgy book of sindo kou. It shows the chemical reactions and products in different envelopes.

My question is can i use the outer envelope which releases moisture/water as a product for preheating of aluminum? If not then what should be the preferred technique for preheating of aluminum?

Thanx all in advance.

 

[waqasmalik]

I have Maxal guide line for welding in my computer. It list downs some of the tips to reduce porosity in aluminum. I am uploading a screenshot, its not a complete page but it has what i want to share with u guys.Please read its third last tip, in the last line it says that DO NOT ATTEMPT TO DRY ALUMINUM USING OXYFUEL TORCH, IT COULD WORSEN THE SITUATION.
Same could be the case with preheating. Though, chemically and mechanicaly cleaned the base material but oxide layer forms immediately and it could be hydrated by moisture from flame.

What do u guys think?

 

[waqasmalik]

here is it

 

[racookpe1978]

OK - You're removing the other sources of hydrogen, but then are you not blowing the oxy-acetylene and partially burned hydrocarbons right back onto the heated and clean Aluminum metals?

Seems like that - the burned soot, the hydro-carbon in the fuel, and the hydrogen in the water as a combustion product are re-introducing what you're trying to remove.

Electric heat? I have not used it on welding aluminum, but I've welded less AL the others.

 

[waqasmalik]

Racookpe

"Seems like that - the burned soot, the hydro-carbon in the fuel, and the hydrogen in the water as a combustion product are re-introducing what you're trying to remove. "

Yes, this is what i thought and literature said.