Gas Entrapment
Gas Entrapment
(OP)
Hi guy, at my investment casting company facing a new type of defect .
Can anyone suggest any solution for this defect ?
Clearly , it's not cause by mis-run defect.
Casting Process: investment casting
Ceramic material : Alumina silicate
Casting temperature: 1500ºC
Mold Temperature : 1150ºC
Casting Material : KHR12C
Fiber wool cover: Yes
Defect type: Gas entrapment lookalike , Round shape hole ,
Material composition : Scrap material (SCH 13Nb) 30% and new material 70%
Casting Weight : Around 50 Kg
Can anyone suggest any solution for this defect ?
Clearly , it's not cause by mis-run defect.
Casting Process: investment casting
Ceramic material : Alumina silicate
Casting temperature: 1500ºC
Mold Temperature : 1150ºC
Casting Material : KHR12C
Fiber wool cover: Yes
Defect type: Gas entrapment lookalike , Round shape hole ,
Material composition : Scrap material (SCH 13Nb) 30% and new material 70%
Casting Weight : Around 50 Kg





RE: Gas Entrapment
"Even,if you are a minority of one, truth is the truth."
Mahatma Gandhi.
RE: Gas Entrapment
Has this casting ever worked correctly?
Are they doing any de-gassing?
What about deoxidizers?
One concern may be how fast they are filling the molds.
They could be filling faster than the venting will handle.
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P.E. Metallurgy, Plymouth Tube
RE: Gas Entrapment
"Even,if you are a minority of one, truth is the truth."
Mahatma Gandhi.
RE: Gas Entrapment
The solidus temperature of this alloy is about 1350C, if you postponed the casting process, or, it took too long time to cast, you could lost temperature. Could increase pouring temp work?
RE: Gas Entrapment
It could also be a large amount of air trapped at the bottom that then rose. But, the fact that many voids are at the mold wall tends to indicate that the gas came through the wall.
RE: Gas Entrapment
Thanks for advice.
But have anyone ever encountered this kind of defect?