How does excess amine gas affect:
1. Core strength
What affect can excess amine have on on castings:
1. Does it produce more gas during casting.
2. Does it disperse into the atmosphere if stood for a period.
Any papers or practical experiences would be greatly appreciated.
Hi, Martin!
The core strength is more dependent on the sand quality than on the amine amount. Amine is a catalyst, it does not participate in the polymer chains building but facilitates this process. But for polymerization binder, you need to have the correct pH sand. If the sand is acid the core strength is falling.
What affect can excess amine have on on castings:
After binder polymerization in the core shooting machine, the core is blown with air and the amine leaves it. In addition, the core does not immediately standing into the mold but some time is stored and the remains amine evaporate. Therefore, there is no amine excess in the mold, if the technology is not broken.
In case entrapped amine remains in core sand, it can be decomposed into elemental N which can cause subsurface or surface porosity in castings.
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