Titanium alloy double-layer thin-wall part roll weld surface crack repairing method

In order to ensure reliable work of an aero-engine actuator case and avoid the problems of oxidation, deformation, cracking and the like of a base material of the actuator case after welding so as to reduce the failure rate, the invention provides a titanium alloy double-layer thin-wall part roll weld surface crack repairing method which comprises the following steps: firstly, drilling crack arresting holes in two ends of a crack; then, based on a patch repairing method, a titanium alloy plate with the same material and the same thickness as the actuator box base body is adopted for manufacturing a patch, the damaged area is completely covered, and then manual argon tungsten-arc welding equipment is adopted for welding the patch and the actuator box base body. In the argon arc welding process, argon is used as shielding gas to prevent titanium alloy oxidation in the argon arc welding process, meanwhile, proper welding process parameters are selected, welding heat input is accurately controlled, and materials