METHOD OF ULTRASONIC INSPECTION OF STATE OF METAL WORKING UNDER CONDITIONS OF CREEPAGE FORECASTING ITS RESIDUAL RESOURCE AND ACOUSTIC UNIT FOR ITS IMPLEMENTATION Russian patent published in 2001 - IPC

FIELD: non- destructive test, heat power industry. SUBSTANCE: increased authenticity of evaluation of state of metal working under conditions of high-temperature creepage, of accuracy of forecasting of its residual resource is achieved by irradiation of surface ultrasonic wave into tested article, by reception of wave passed through article with constant base between radiator and detector. Propagation time of said wave is measured first in reference article, then in tested article in direction of maximal tensions acting in metal during its usage and across same section in direction perpendicular to it. Relative change of velocity in each mentioned directions are determined. State of metal is evaluated by known dependence of relative change of velocity on density of micropores with use of maximum value of obtained value of density of micropores. Then residual resource is found. Acoustic unit is made up of two converters interconnected by means of flexible metal plates and magnets. Prism of radiating converter can be fitted with one or three additional piezoplates. Additional plate or one of three additional plates is placed in symmetry to radiating plate with regard to plane passing through point of injection of waves into article and perpendicular to working and side surfaces of prism. Two other additional plates are located one in symmetry to another with reference to same plane. One of them is radiator and another plate is detector of ultrasonic Lamb waves and points of injection of waves of all plates into article match. Prism of another converter can be equipped with one additional plate which is detector of Lamb waves and has same point of injection of wave as plate receiving surface waves. All plates are located at equal distances from points of injection of waves of corresponding prisms into article. Flexible metal plate anchored on working surface of prism has same coefficient of linear expansion as metal of article. Axes of magnets are perpendicular to working surfaces of prisms and lie in one plane with point of injection of waves into article. Prisms of converters can comprise two parts interbonded along plane passing through point of injection of waves into article and perpendicular to working and side surfaces of prisms. EFFECT: increased authenticity of evaluation of state of metal working under conditions of high-temperature creepage. 6 cl, 8 dwg