Method of detecting corrosion rate of member of steel material
First Claim
1. A method of detecting the rate of corrosion of an existing steel structure installed in a corrosive environment, said steel structure having a surface section to which a probe is to be attached for detecting said corrosion rate, said method comprising the steps of:
- removing deposits from said surface section of said steel structure so that an AC impedance of said surface section, when electrochemically measured by application of potential variation thereto at a predetermined high frequency range, takes a first value within a range of 5 Ω
cm2 to 50 Ω
cm2 ;
measuring the impedance of said measurement surface by application of potential variation at a predetermined low frequency range to obtain a second AC impedance value;
calculating the difference between said first and second measured values to detect a corrosion-reaction resistance of said surface section; and
determining the rate of corrosion of said surface section on the basis of said detected corrosion-reaction resistance of said surface section and according to a precalculation relation between the rate of corrosion and the corrosion-reaction resistance;
whereby the corrosion rate can be determined directly on said surface section without the need for a separate corrodible testing means.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of detecting the rate of corrosion of an existing steel structure installed in a corrosive environment is disclosed. The method includes treating a measurement surface of the member so that an AC impedance of the measurement surface, when electrochemically measured at a predetermined high frequency range of potential variation applied to the measured surface, takes a first valve within a predetermined range; and second value of the impedance is then electrochemically measured at a low frequency range of potential variation applied thereto. The difference between the first and second values is calculated to detect the corrosion-reaction resistance of the surface and the rate of corrosion is determined on the basis of the detected corrosion-reaction resistance and according to a pre-calculated relation between the rate of corrosion and the corrosion-reaction resistance.
22 Citations
3 Claims
-
1. A method of detecting the rate of corrosion of an existing steel structure installed in a corrosive environment, said steel structure having a surface section to which a probe is to be attached for detecting said corrosion rate, said method comprising the steps of:
-
removing deposits from said surface section of said steel structure so that an AC impedance of said surface section, when electrochemically measured by application of potential variation thereto at a predetermined high frequency range, takes a first value within a range of 5 Ω
cm2 to 50 Ω
cm2 ;measuring the impedance of said measurement surface by application of potential variation at a predetermined low frequency range to obtain a second AC impedance value; calculating the difference between said first and second measured values to detect a corrosion-reaction resistance of said surface section; and determining the rate of corrosion of said surface section on the basis of said detected corrosion-reaction resistance of said surface section and according to a precalculation relation between the rate of corrosion and the corrosion-reaction resistance; whereby the corrosion rate can be determined directly on said surface section without the need for a separate corrodible testing means. - View Dependent Claims (2, 3)
-
Specification
-
- Resources
-
Current AssigneeNippon Steel Corporation
-
Original AssigneeNippon Steel Corporation
-
InventorsOka, Tomoki, Kihira, Hiroshi, Ito, Satoshi, Matsuoka, Kazumi
-
Primary Examiner(s)Richman, Barry S.
-
Assistant Examiner(s)ALEXANDER, LYLE
-
Application NumberUS07/001,734Time in Patent Office746 DaysField of Search436/6, 324/65 CR, 324/65 P, 324/444, 324/445, 324/446, 204/1 C, 422/53US Class Current205/777CPC Class CodesG01N 17/02 Electrochemical measuring s...
