Xi Y.,Hefei University of Technology |
Zhang J.-W.,Hefei JAC Casting Co. |
Zhu H.,Hefei JAC Casting Co.
Zhuzao/Foundry | Year: 2012
In several hours after shot-blasting, a large number of rusty spots emerged on the inner surface of 4DA cylinder casting. By comparing the morphology and chemical composition between the rusty spots and the normal surface, and analyzing the casting process, it is believed that during the post inoculation, Si-Ba inoculant is not completely melted into the melt, and some residues enriched on the casting surface. Ba in the residues reacts with H 2O, which generates Ba(OH) 2. The alkaline environment, interaction with water based coats and the core resin, causes the depolarization action to promote electrochemical corrosion on the iron surface. It can eliminate abnormal rusty spots to utilize 75Si-Fe metal-stream inoculation as a substitute for Si-Ba.