The invention discloses a resin self-hardening core sand for
casting train iron castings and a preparing method of the resin self-hardening core sand. The resin self-hardening core sand is prepared from, by weight, 160-180 parts of sea sand, 20-30 parts of carborundum, 16-20 parts of refiring magnesia, 10-14 parts of paper clay, 6-8 parts of chalk soil, 10-15 parts of
furan resin, 12-14 parts of
cashew nut shell oil modified phenolic resin, 4-6 parts of
polyimide, 3-5 parts of
rare earth tailing, 5-7 parts of pandermite, 8-10 parts of waste
foam glass, 3-5 parts of ferro
silicon nitride, 1-2 parts of N-(beta-aminoethyl)-gamma-aminopropyl triethoxy
silane, 2-4 parts of p-toluenesulfonic acid, 3-5 parts of
phosphoric acid, 4-6 parts of
castor oil maleic anhydride acid esters, 8-10 parts of
triphenylmethane triisocyanate and 2-4 parts of
styrene. According to the
furan resin self-hardening sand, mixed resin is adopted, the method of adding single resin is changed, mutual effects between different kinds of resin including the
furan resin, the
cashew nut shell oil modified phenolic resin, the
polyimide and the like are adopted for enabling the core sand to have the beneficial effects of being high in strength, small in gas-forming amount, low in thermal expansivity, good in breathability, good in collapsibility and the like, and the produced castings are high
in degree of precision and good in surface quality.