Investment casting method of heat-resistant steel exhaust manifold for automobile

The invention belongs to a metal casting technology and particularly relates to an investment casting method of a heat-resistant steel exhaust manifold for an automobile. The method comprises the steps of wax mould manufacturing, shell manufacturing, alloy smelting, pouring, shakeout and cleaning. The method has the benefits that the common defects of partial shrinkage, hole shrinkage and the like of the heat-resistant steel exhaust manifold for an automobile engine can be eliminated or reduced, and the process yield is higher.