AC2B aluminum Degassing

[HiGroove]

I am looking for potential improvements for the Degassing of AC2B Aluminum.
We are using rotary degassing unit with liquid argon.

1) Are there any standards on how deep the degassing unit should be below the surface of the melt ?

2) Are there any standards on the rotational speed of the degassing unit ?

3) Is there any relationship with the Diameter of the rotary unit and degassing potential ?

Thanks for you help.

 

[Modey3]

Casting defects and prevention is one of my major research interests. Have you heard of the man named Dr. John Campbell? His entire research deals inproving casting quality. He put out a book called "Castings" which should help if what I say dosen't help.
First and foremost im not a fan of degassing units that use stripping as a means of hydrogen removal. Unless the degassing is done in conjunction with a vacuum or in a argon controlled atmosphere to prevent surface oxidation, the enert gas bubbles will break apart the protective oxide layer by folding the oxide films as the bubble passes trough the surface. My lab tried this technique casting A319 alloys using a degassing lance with the result of getting terrible porosity. I recommend just degassing in a vaccum
Now that my opinon has been said. The larger rotary diameter will diperse the bubbles better therefore giving you better mass transfer. Plenty of work has been done in regards to this so look in the literature. The rotational speed will ahve the same effect if its increased. The rotary unit should be as deep below the surface as you can but it. I hope this helps.

Modey3