METHOD AND APPARATUS FOR PREDICTING METAL SHEET RESIDUAL STRESS BASED ON MEASUREMENT OF WARPAGE AMOUNT CAUSED BY RESIDUAL STRESS RELEASE

摘要

A method for predicting the metal sheet residual stress based on measurement of the warpage amount caused by residual stress release, comprising: using one of the X-ray method, the blind hole method, the ultrasonic method, the crack compliance method or the finite element analysis method to perform residual stress measurement on sheets of different thicknesses; cutting a sample by machining, the residual stress release causing the sheets to warp, measuring the warpage amounts using a displacement sensor, so as to obtain the relationship, for the sheets of different thicknesses, between the residual stress and the warpage amount; obtaining a quadratic equation by means of curve fitting: y = ax2 + bx + c, where x - residual stress, y - warpage amount, and a, b and c represent the fitting coefficient; and on the basis of the established functional relationship between the residual stress and the warpage amount, measuring the warpage amount y at a specific linear cutting percentage, and calculating the residual stress according to formula (I). Also provided is an apparatus for measuring the metal slab deformation amount caused by residual stress release. The present invention can quickly evaluate the magnitude of the overall residual stress of the material, and the fluctuation of the residual stress between batches, facilitating to establish sheet residual stress control criteria.