A low-cost core for investment casting formed with hot-box process was investigated.The core consists of furan resin as binder at room temperature and liquid aluminum dihydrogen phosphate which plays the dual roles in curing agent and high-temperature binder

and it is assisted with low-temperature dipping enhancing processing.Taking pre-firing

post-firing and high temperature residual strength as bench marks for resin sand core

influential factors such as resin types

resin amounts

granularity of sand

amounts of aluminum dihydrogen phosphate

core dipping times

were optimized by orthogonal testing.The results reveal that proportion in which resin content accounts for 2%～3% sand weight and aluminum dihydrogen phosphate addition accounts for 2%～4% sand weight exhibits availability.And then the cores were manufactured with the optimized proportion for investment casting evaluation tests.The results show that the cores have the advantages such as separate firing being not needed

low cost and very low residual strength of 3.45～5.0MPa

meeting the requirements of investment casting cores with relatively simple shape.