Originally published in the May 2017 issue of Foundry Management & Technology.
by Alexander Brown
Controlling raw materials is critical to the success of iron casting production from green sand systems. The base silica sand is often overlooked, with the main focus on bentonite additions. Carbonaceous additives can be considered a “necessary evil” to ensure a good surface finish and reduction in sand-related surface defects. Other additives are used when systems get out of balance, and these will further complicate the complexity of green sand systems.
For castings requiring cores, this becomes a bigger issue, as many different resin systems are employed for core production, and these must be taken into consideration when controlling both the carbonaceous levels and the overall grading of the sand system. The twin effects on additional carbon and loss-on-ignition and overall sand grading need careful understanding and control.