Method for detecting residual stress of deep layer of workpiece

Abstract

The invention discloses a method for detecting residual stress of a deep layer of a workpiece. The method comprises the following steps: firstly, detecting residual stress on a surface layer of the workpiece by using a laser speckle blind hole method; secondly, locally stripping a detected layer through an electrolytic machining process; thirdly, repeating the residual stress detection process andthe electrolytic stripping process for many times until the residual stress of a target position is detected; fourthly, calculating correction coefficients of different depth positions according to basic parameters of the laser speckle blind hole method and the electrolytic stripping method; and fifthly, obtaining an original residual stress value of the deep layer of the workpiece on the basis of a correction coefficient and a residual stress correction formula of the repeated stripping process. According to the method in the invention, the laser speckle blind hole method and the electrolytic machining process are combined, the detection of the residual stress of the surface layer and the deep layer of the workpiece can be realized, the residual stress distribution situation in the depthdirection of the workpiece is obtained, the detection efficiency is high, and the result is accurate and reliable. Based on the method in the invention, the residual stress of the whole workpiece canbe better represented, the residual stress eliminating and controlling process can be better guided, and the influence of the residual stress on deformation is better predicted, so that the machiningprecision and the service life of the workpiece are improved.

Description

technical field [0001] The invention relates to the field of residual stress detection, and more specifically, relates to a method for detecting deep residual stress of a workpiece. Background technique [0002] Residual stress refers to the stress remaining inside the workpiece when the workpiece has gone through a series of processing processes and unloaded, and the workpiece has no external load. Common machining processes, some surface treatment processes, and surface strengthening processes will lead to the generation of residual stress, such as common cutting, casting, forging and shot peening processes. Residual stress is generally harmful to the workpiece. With the gradual release of residual stress, the workpiece will often be deformed, warped or even cracked. Therefore, it is of great significance to effectively detect and control the residual stress of the workpiece during processing. [0003] Commonly used residual stress testing methods are usually divided int...

AI Technical Summary

Problems solved by technology

When the detection depth is deep, the traditional incremental X-ray method takes a long time and has low efficiency

At the same time, the traditional incremental X-ray method is based on X-ray diffraction, so it has high requirements for the microstructure of the workpiece, and it can only be used to detect the residual stress of fine-grained and non-textured workpieces, so the detection limitations are relatively large

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