Method applied to detect nanocrystallization of fluid valve inner surface

The invention provides a method applied to detect nanocrystallization of the fluid valve inner surface. The method comprises the following processes that S1, a fluid valve inner surface sample is prepared; S2, residue stress of the surface of an area at which fiber laser is used for laser shock of the fluid valve inner surface sample is detected; S3, a two-dimensional coordinate system of different laser shock strengthening parameters and FWHM is established, and a curve graph of which the FWHM changes along with the different laser shock strengthening parameters of a same crystal face is drawn; S4, the depth of a laser shock strengthening area is detected by a contourgraph and the like, and a depth changing curve is established; S5, through a transmission electron microscope and electrondiffraction experiment, it is verified that residue stress in three directions is approximately equal, a FWHM value is 2.86 degrees, the depth achieves 12.5[mu]m and the shocking strengthening times is once when the laser pow