Precautions for Proportioning of Molding and Core Mixtures: .
(1) When preparing the mixture for large carbon steel or manganese steel castings, chromite sand can be used as the surface sand, quartz sand or old sand as the back sand. The amount of face sand required is calculated as 2 inches of face sand per inch of casting thickness.
(2) The binder and desiccant must be mixed first, then added to the chromite sand, and then fully mixed for a long time to ensure The binder properly coats the grit, while the crosslinking agent is added and ground sufficiently.
(3) The acid requirement of chromite furan resin sand is about 10% more than that of quartz sand. Phosphoric acid should be added first to cover the sand, and then add resin until the end of mixing.
