The best method of getting aluminium into solution in Cr/Ni/Fe alloy?
The best method of getting aluminium into solution in Cr/Ni/Fe alloy?
(OP)
Hi, I am conducting a project in dimensional control of investment casting. I wonder if anyone can help me with the following:
What is the best method of getting aluminium into solution in a Cr/Ni/Fe alloy using an electric induction furnace? I am gaining good yield just by adding pure Al to molten bath, but some aluminium appears to melt on contact and remains as a film on metal bath surface. After removing any slag this is very difficult to remove. This surplus Al appears to cause casting inclusions as it oxidises readily.
It is not a solubility problem as I have achieved a higher % of aluminium in solution previously.
Any Ideas?
What is the best method of getting aluminium into solution in a Cr/Ni/Fe alloy using an electric induction furnace? I am gaining good yield just by adding pure Al to molten bath, but some aluminium appears to melt on contact and remains as a film on metal bath surface. After removing any slag this is very difficult to remove. This surplus Al appears to cause casting inclusions as it oxidises readily.
It is not a solubility problem as I have achieved a higher % of aluminium in solution previously.
Any Ideas?





RE: The best method of getting aluminium into solution in Cr/Ni/Fe alloy?
RE: The best method of getting aluminium into solution in Cr/Ni/Fe alloy?
You really want to be as cold as possible when you add the Al. You will gain some temp due to the exotherm of the Al burning the residual oxygen out of your melt. You also want to have enought headroom on the temperature to allow you to go to full power after the Al addition in order to get effective EM stirring. You may want to add a portion of your Fe or Ni after the Al. To cool the bath and to help physically cover it.
If you are not using another deoxidizer first, and an argon melt blanket, reliable recoveries will be hard.
I used to add 7% Al to Co based alloys.
What size is the furnace? What size and freq is the power?
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: The best method of getting aluminium into solution in Cr/Ni/Fe alloy?
RE: The best method of getting aluminium into solution in Cr/Ni/Fe alloy?
For maximum recovery, first deoxidize with some sacrificial aluminum. Let the oxide float to the slag, then add the amount of aluminum you need as coated Al wire through the slag, and you should get 90+% recovery.
RE: The best method of getting aluminium into solution in Cr/Ni/Fe alloy?
RE: The best method of getting aluminium into solution in Cr/Ni/Fe alloy?