Ultrasonic Residual Stress Test Method for Macroscopically Out-of-Plane Deformed Flat Weldments

Abstract

The invention discloses an ultrasonic wave residual stress test method for a macro outer deformation flat weldment. The method comprises the following steps: A1, adhering foil gauges to areas to be detected of the flat weldment, wherein the direction of strain tested by the foil gauges is consistent with the spreading direction of ultrasonic waves of an ultrasonic wave residual stress test about to be performed; A2, applying external forces to enable the macro outer deformation of the flat weldment to disappear and maintaining a flat state; A3, reading strain values epsilon detected by the foil gauges in the areas to be detected, and calculating forces sigma w generated by the areas to be detected for eliminating reversible deformation, wherein sigma w=E epsilon, and E is an elastic modulus of a flat weldment material in a strain test direction; A4, removing the foil gauges on the areas to be detected, performing the ultrasonic wave residual stress test on the areas to be detected so as to obtain residual stress measured values sigma c; and A5, according to the forces sigma w generated by the areas to be detected for eliminating the reversible deformation and the residual stress measured values sigma c, determining actual residual stress values sigma of the areas to be detected of the flat weldment, wherein sigma=sigma c-sigma w. The method provided by the invention can remarkably improve the residual stress test precision of ultrasonic waves for a flat weldment with macro outer deformation.

Description

technical field [0001] The invention relates to an ultrasonic residual stress test method for solving the change of the ultrasonic coupling state and propagation path caused by the macroscopic surface shape of a flat plate weldment, and belongs to the field of non-destructive detection of welding residual stress. Background technique [0002] Friction stir welding uses frictional heat and plastic deformation heat as the welding heat source. A cylinder or other shape (such as a threaded cylinder) stirring needle is inserted into the joint of the workpiece, and through the high-speed rotation of the welding head, it is combined with the The material of the welded workpiece rubs against each other, which increases the temperature of the material at the joint and softens it. Friction stir welding belongs to non-melting welding. It has the advantages of no residual height after welding, less welding defects, good weld shape, weld strength can reach the strength of base metal, and...

AI Technical Summary

Problems solved by technology

This method can solve the problem of poor coupling state of the fixed ultrasonic wedge on the test plane of the weldment, and the difference between the actual ultrasonic propagation path and the nominal path, and can significantly improve the residual stress test accuracy of ultrasonic waves on flat weldments with macroscopic out-of-plane deformation.

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