METHOD TO DETERMINE DEPTH OF SURFACE CORROSION OF METAL STRUCTURES Russian patent published in 2012 - IPC G01N17/00 

FIELD: construction.

SUBSTANCE: method is realised by facilities with formation of a microcone on a structure surface with a depth exceeding the thickness of a rust layer. The thickness of the corrosion layer h is determined with the help of an optical instrument by the width of a corrosion ring η with subsequent recalculation using the following formula: h = ηtgα / 2, where α - angle of drill sharpening. The method is realised in the following manner. Areas mostly affected by corrosion are identified in a metal structure. A layer of a setting composition, for instance, a quick-drying enamel, is applied onto an area of the surface damaged with corrosion and selected for investigation. After enamel hardening on this surface using a drill with a diametre of several mm (3-4 mm) a microcrater is drilled to the depth exceeding the rust thickness determined in an experimental manner. Than an optical instrument is placed onto the tested surface normally to the diametre of the drilled microcrater, providing for detection of linear dimensions of measured fragments of the cone. With the help of a calibrated scale of the optical instrument a linear size of the correlated layer of the ring is determined as η enclosed between a pure metal and an enamel layer that fixed the rust. Substantially dimensions η (a horizontal projection of a cone face) and h (thickness of a rust layer) are legs of a right-angled triangle formed by a cone generatrix and an axis of its symmetry. On the fig. 6 there is the result of survey from practice of investigation of a metal structure via an optical instrument MPB-2 with a division price of 0.05 mm determining measurement accuracy. When inspecting a drilled area, the horizontal size of the corrosion layer is visible as enclosed between the enamel and the pure metal equal to 0.15 mm. Upon detection of the corrosion size the drilled areas are filled with a strong composition, if required: a primer, a glue composition are applied onto them, cold welding and sealing is carried out, etc. The formula contains one claim and one subclaim.

EFFECT: higher accuracy of measurement by direct detection of parameters of their surface damage with rust, development of an instrumental method to directly detect parameters of rust damage of the available surface of metal with the purpose to exclude samples or slices.

2 cl, 6 dwg