Understanding the role of cerium during VIM refining of nickel-chromium and nickel-iron alloys
Abstract
The effect of cerium addition on the VIM refining process of oxygen, sulfur, and nitrogen in a nickel-chromium alloy and the Udimet 901 iron-nickel-base superalloy is presented. It was found that cerium reduces sulfur and oxygen content effectively through the formation of cerium oxides, sulfides, and oxysulfides but did not reduce the already low nitrogen content. The kinetics of oxygen and sulfur depletion in the VIM heats follow the first order reaction rate theory and the proposed mechanism is that of the drift of inclusions to crucible skulls. The maximum addition of cerium to iron-nickel-base alloys is limited by segregation effects that lead to hot shortness.
- Publication:
-
Metallurgical Transactions B
- Pub Date:
- December 1982
- DOI:
- 10.1007/BF02650018
- Bibcode:
- 1982MTB....13..603L
- Keywords:
-
- Metallurgical Transaction;
- Oxysulfide;
- Vacuum Induction Melting;
- Inclusion Removal;
- Refining Time