Method for producing heavy machine multi-layer water cavity exhaust pipe through combined sand-lined iron mold casting

The invention discloses a method for producing a heavy machine multi-layer water cavity exhaust pipe through combined sand-lined iron mold casting. An integral iron mold is adopted as an upper outer sand box. An inner cavity of the iron mold is manufactured in a mold-following mode according to the shape of the heavy machine complex multi-layer water cavity exhaust pipe, and the thickness of a mold-following sand lining layer is 12mm-20mm. A pouring system comprises a pouring cup, a sprue and a runner gate. The core head portion of an upper half mold is partially provided with exhaust hole needles which penetrate out of a box face. A base composite type mold core of a detachable structure is adopted as a lower outer sand box. The middle of an upper mold bottom plate and the bottom of a lower mold bottom plate are each provided with a heating device. Both the mold temperature and the iron mold temperature are controlled to range from 180 DEG C to 240 DEG C, and sand shooting is performed after the temperature