FIELD: non-destructive inspection.
SUBSTANCE: method of electric non-destructive inspection of residual stresses in items made of current-conducting materials is based upon layer-by-layer measurement of electric conductivity of tested part of material by means of preliminary punching oxide layer and other coatings having high electric resistance till contact with surface with inspected material is achieved by sharp prods of detector. Detector is connected to ac voltmeter. Matter of contact is judged from sharp drop of resistance registered by ohmmeter tuned to its highest frequency. Electric resistance of inspected part of material is performed at frequency proving inspection of thickness of its surface layer. Electric resistance is firstly measured at constant base preliminary on preliminary chosen sample of set of inspected identical items after they had been subject to similar technological or exploitation influence, namely, on set of thicknesses of surface layer. Then residual stresses are measured on same thicknesses of surface layer by arbitrary coulometer method. Dependences of residual stresses on electric resistances are built for those items for any thickness of surface layer of material. After that residual stresses in thicknesses, where electric resistance and residual stresses had been measured during at non-destructive inspection of those items on base of measured values of electric resistances at the same constant base.
EFFECT: improved efficiency of quality inspection of values of residual stresses of inspected power items.
3 cl, 2 tbl, 2 dwg
