Surfacing forming remanufacturing method for magnesium alloy part

The invention discloses a surfacing forming remanufacturing method for a magnesium alloy part, and belongs to the field of remanufacturing waste and damaged parts. The method comprises the steps of removing the defects such as looseness, air holes and cracks on the surface of the part in a grinding mode, using the surfacing forming technology for precisely recovering part size losses, immediately using flames for heating a surfacing forming layer to the melting point, ranging from 100 DEG C to 200 DEG C, of magnesium alloy after surfacing forming is completed, and using a friction stir welding device for conducting round friction stir postprocessing on the surfacing forming layer. According to the surfacing forming remanufacturing method for the magnesium alloy part, remanufactured zone metallographic structure crystalline grains are uniform and fine, and no obvious coarse crystalline grain heat-affected zones exist; no hot cracks or air holes are generated even under the situation of large-restraint and large-area defect zone remanufacturing; the residual stress generated in the remanufacturing process finally is quite small, and the strength of the remanufacturing zone is high.