A Laser Shock Strengthening Method for Stamped Sheets Based on Image Grid Method

Abstract

The invention relates to the field of laser processing, in particular to a method for laser shock strengthening of a stamped plate based on an image grid method. First, a layer of grid is attached to the flat sample by laser marking, and the images before and after the deformation of the object are transmitted to the computer through the CCD camera, and the deformation area of ​​the stamping part is divided into several curved surface slices by using 3D software, and along the curved surface slice The normal direction of the outer surface is projected to the two-dimensional datum plane, and the lateral deformation and longitudinal deformation of the grid unit are calculated according to the point coordinates in this plane. Then establish the corresponding relationship between the deformation amount and the overlapping rate in the corresponding laser shock parameters, so as to optimize the process parameters of laser shock strengthening and realize the uniform surface strengthening of stamping parts. The method realizes effective laser shock strengthening on the stamping plate, improves the stress distribution of the stamping part, reduces local stress concentration, and improves the fatigue strength of the stamping part.

Description

technical field [0001] The invention relates to the field of laser processing, specifically a laser shock uniform strengthening method for stamping plate parts with large deformation, in particular a laser shock strengthening method for stamping plate based on image grid method, especially suitable for automobile blades and uniform strengthening of key supports. Background technique [0002] With the rapid development of the automobile industry, automobile factories continue to introduce various new models. Body covering parts are the main components of the body, and the requirements for the stamping process are getting higher and higher. However, during the stamping process of body parts, local strain distribution will be uneven, which will make the material flow poor and cause strain concentration, which will lead to cracking. [0003] A widely used method for measuring the plastic deformation of metals, especially the value and distribution of large plastic deformations,...

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Problems solved by technology

[0004] Laser shock peening is a new type of surface strengthening technology, mainly using short pulses (tens of nanoseconds), high peak power density (>10 9 W / cm 2 ) laser radiation on the metal surface, the laser beam passes through the constrained layer and is absorbed by the absorbing layer, and the absorbing layer obtains energy to form explosive gasification and evaporation, generating high temperature and high pressure plasma, due to the constraints of the outer constrained layer, the plasma forms a high pressure The shock wave propagates to the inside of the material, and plastic deformation occurs on the surface of the material by using the force effect of the shock wave, which changes the microstructure of the surface material, and at the same time generates residual compressive stress in the impact area, improving the strength, hardness, wear resistance and stress corrosion resistance of the material performance, can effectively improve the stress distribution of materials, but due to the uneven distribution of local strain of stamping parts, it is impossible to effectively carry out targeted laser shock strengthening on stamping parts

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