The invention provides a precision-
investment casting method for easily-oxidized metals. The precision-
investment casting method comprises the following steps of (1) preparation of a
surface layer of a mold shell, specifically, a
refractory powder is added into a binder and evenly mixed, a
wetting agent and an antiforming agent are further added, and even mixing is conducted to prepare
surface layer coating; and the
coating is smeared on a
wax patter, and after
drying, the above operations are repeated for many times to form a
surface layer mold shell; (2) preparation of a reinforcement layer of the mold shell, specifically, a
bauxite powder is added into a silica
sol binder and evenly mixed,
bauxite sand is adopted to conduct stuccoing, and after
drying, the above operations are repeated for many times to form a reinforcement layer mold shell; (3) mold shell dewaxing and
roasting, specifically, an
infrared dewaxing technology is adopted; and (4) melting and pouring, a vacuum consumable kish melting method is adopted to conduct melting, and a centrifugal pouring technology is adopted to conduct pouring. According to the precision-
investment casting method for easily-oxidized metals, a
casting produced by adopting the method is precise in size, the minimum wall thickness is small than or equal to 1.0 mm, the
surface roughness is smaller than or equal to 6.3 mu m, the
surface reaction layer is smaller than or equal to 0.03 mm, and the surface is free of the defects of cold shut, flow marks, microcracks and the like; and moreover the production cost is reduced, the
production cycle is shortened, and the method is suitable for volume production.