Performance testing method of valve needle type bolt stretching and leveling device

The invention belongs to the technical field of nuclear power plant bolt stretcher testing, and relates to a performance testing method of a valve needle type bolt stretching leveling device, which comprises the following steps: S1, checking before testing; S2, testing action functions; S3, testing automatic reset function: testing whether the piston rod is automatically reset; S4, adjusting accuracy test: under the rated load of 30t, switching on the electric magnet on in a single inching manner, enabling the switching-on time to be within 3s, and measuring the single inching falling adjusting accuracy in the whole stroke range; S5, conducting a pressure maintaining test, under the rated load of 30 t, keeping the stroke of the piston within 75 mm, conducting standing for 1 h, and measuring and recording the displacement of the piston rod of the levelness adjusting device; S6, testing overload; S7, conducting fatigue testing, under the rated load of 300 kN, switching on an electric magnet on in an inching mod