Insert of pour-around die casting, rust preventive oil for insert of pour-around die casting, and method for pouring around an insert

Insert of pour-around die casting, rust preventive oil for insert of pour-around die casting, and method for pouring around an insert Disclosed are an insert of pour-around die casting, which is incorporated by an aluminum alloy die casting and has an organic film formed on the surface of the insert, wherein the organic film contains a higher fatty acid ester, a petroleum sulfonate and a mineral oil and has a thickness of from 0.5 to 2 m, a rust preventive oil used therefor, and a method for incorporating the insert with an aluminum alloy die casting.