METHOD FOR DETERMINATION OF RESIDUAL STRESSES IN WELD METAL WELDED JOINTS OF PIPELINES (VERSIONS) Russian patent published in 2020 - IPC G01N29/07 

FIELD: antenna equipment.

SUBSTANCE: use: for definition of quality of welded joints of pipelines fabrication and for determination of residual value of pipelines. Summary of invention consists in the fact that on the analyzed section of the pipeline an ultrasonic echo-method is used to measure the propagation time of the longitudinal wave and transverse waves polarized along and across the pipe axis, and based on the measurement results, the welded joint stress state characteristics are determined, wherefore, for the specific type of pipes, by the simulation, the cross-section position is pre-determined, in which balancing annular stresses in the base metal reach minimum values, and the value of the equilibration coefficient equal to the ratio of the maximum residual tensile membrane annular stresses in the seam metal to the value of the minimum residual compressing membrane annular stresses in the base metal, then, prior to the beginning of the welded joint manufacturing, in the balancing sections, measuring the initial values of propagation time of the longitudinal wave and transverse waves polarized along and across the pipe axis, after making the welded joint at the same measurement points, measuring working time values of propagation of the same types of waves, based on measurement results using equations of acousto-elasticity for a two-axial stress state for each measurement section, determining the values of membrane longitudinal and annular stresses, as well as bending moments, using which, based on the principle of balancing membrane stress and taking into account the coefficient of balancing, determining maximum values of residual longitudinal and annular local stresses in weld metal.

EFFECT: enabling determination of separately longitudinal and annular residual stresses.

2 cl, 7 dwg