Ultrasonic method for measuring residual stress of cambered workpiece

Abstract

An ultrasonic method for measuring residual stress of a cambered workpiece comprises the following steps: S1, performing stress testing to obtain a function curve t0x=M (x) between a propagation distance x and the propagation time t0x of a longitudinal critical refraction wave in a zero-stress plate calibration block; S2, performing stress testing to obtain a function curve Kx=F (x) of a nominal acoustic elasticity coefficient Kx corresponding to the propagation distance x; S3, measuring the propagation time t of the longitudinal critical refraction wave in a cambered workpiece; S4, measuring a propagation distance a of the longitudinal critical refraction wave in the cambered workpiece; S5, according to the function curve t0x=M (x) and the function curve Kx=F (x), obtaining the propagation time t0a and a nominal acoustic elasticity coefficient Ka corresponding to the propagation distance a in a zero-stress state, and then according to a formula sigma=K (t-t0), working out the residual stress of the cambered workpiece to be measured. By the ultrasonic method, the residual stress of the cambered workpiece can be measured conveniently and fast; meanwhile, the problem that in the prior art, calibration is inaccurate is solved, so that the ultrasonic measurement accuracy of the residual stress of the cambered workpiece is greatly improved.

Description

technical field [0001] The invention relates to a method for measuring the residual stress of a curved surface workpiece by an ultrasonic method, belonging to the field of non-destructive measurement of welding residual stress. Background technique [0002] Welding is the most widely used technology in industry at present, and the welding technology has high connection strength and good sealing performance. Because the main way of causing welding damage is the damage caused by excessive residual stress in the welded joint, there are increasingly strict requirements on the reliability of the welded structure. Therefore, in the production process of welded structures, it is very important to measure the welding residual stress accurately and quickly. [0003] At present, the main methods for measuring welding residual stress are divided into two categories: destructive testing and nondestructive testing. The methods of destructive testing include the blind hole method and th...

AI Technical Summary

Problems solved by technology

This method can conveniently and quickly measure the residual stress of curved surface workpieces, and at the same time solve the problem of inaccurate calibration in the prior art, and greatly improve the accuracy of ultrasonic measurement of residual stress of curved surface workpieces

Images