Surfacing process of pressurized water reactor nuclear power coolant main pump

The invention discloses a surfacing welding process for a pressurized water reactor nuclear power coolant main pump. The surfacing welding process comprises the following steps that nuclear power coolant main pump welding base metal is selected according to the design requirement of RCC-M; pre-welding pretreatment and inspection are conducted on a to-be-welded area of the workpiece; the pump shell is placed on a special displacement tool, and the inner welding surface and the outer welding surface are placed at the horizontal position or the vertical position; a double-tungsten-electrode welding gun is adopted, and the welding gun is arranged near the to-be-welded area of the workpiece in the mode that two tungsten electrodes are longitudinally arranged in the welding direction; preheating the surface to be welded; surfacing of a stainless steel transition layer is conducted on the preheated surface; post-heating the welding area and the adjacent area thereof; cleaning the surface of the stainless steel trans