The invention discloses a use method for an
underwater friction stitch
welding draining device. Firstly, a workpiece and a stopper are installed; and then a flexible shell of the draining device is connected to a spindle head through a clamp, the flexible shell is connected with a
flange through a clamp, and a magnetic suction cup is fixed to the
flange so as to be attached to the surface of the workpiece. A magnetic suction cup switch is turned on, magnetic attraction force can be transmitted to the
flange through a base plate, and
sponge is pressed tightly and makes tight contact with the surface of the workpiece. An air circuit is started at the same time, draining is conducted before
welding is started, and the
water level is located below the workpiece. A friction stitch
welding device is started, a welding
machine spindle is moved downwards, the flexible shell contracts in the height direction, a sample makes contact with
base metal workpiece, the
welding process is started, and the whole process can be observed through the transparent flexible shell. According to the use method, the purpose that that due to the fact that the welding quality during
underwater friction stitch welding is relatively poor, and an air environment is built
underwater for welding is achieved; and the purposes that the
underwater welding process is optimized, and the technology parameter range is enlarged are achieved.