METHOD FOR MEASURING THE DEPTH OF SURFACE CRACK BY ELECTRICAL POTENTIAL METHOD Russian patent published in 2021 - IPC G01N27/20 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of non-destructive testing, it can be used to measure the depth of surface cracks in metals. The method of measuring the depth of a surface crack by the electrical potential method is as follows. Current electrodes 2 and 3 are installed at points T₁ and T₂, located opposite each other on different sides relatively to crack 9. Contact points P₁ and P₂ of potential electrodes 4 and 5 are selected so that they are located one after the other on one of the sides of the crack and are displaced in one direction along the crack from line T₁T₂. Potential electrode 6 is installed at contact point P₃, located on the other side of crack 9 relatively to points P₁ and P₂. The first pair of potential electrodes connected to the first input of electronic unit 8 is formed between potential electrodes 4 and 5 installed at points P₁ and P₂. The second pair of potential electrodes connected to the second input of electronic unit 8 is formed between potential electrodes 4 and 6 installed at points P₁ and P₃. After installing the electrodes, the alternating sinusoidal electric current generated by source 1 is passed, introduced by current electrodes 2 and 3 at contact points T₁, T₂. Voltage U_V1 between electrodes 4 and 6 and U_V2 between electrodes 4 and 5 is measured using electronic unit 8. Ratio Re(U_V1/U_V2) is calculated from measured voltages U_V1 and U_V2 and the depth of the crack is estimated by it. Ratio Re(U_V1/U_V2) is uniquely related to depth h of the crack and practically does not depend on the electromagnetic characteristics of the controlled object with the crack.

EFFECT: increase in sensitivity to the depth of the crack and an increase in the range of its measurement.

2 cl, 7 dwg