초록 ▼

A method and system for detecting and preventing Stress Corrosion Cracking (SCC) in buried pipelines or other structures is presented. The basic principle of the invention is to use a plurality of test coupons which are placed in the same environment as a pipeline or other structure of interest as i

A method and system for detecting and preventing Stress Corrosion Cracking (SCC) in buried pipelines or other structures is presented. The basic principle of the invention is to use a plurality of test coupons which are placed in the same environment as a pipeline or other structure of interest as indicators of the development of SCC in the structure of interest. Loading and temperature of the test coupons are controlled. The test coupons are given a range of different Cathodic Protection (CP) levels, with the range of CP levels selected so as to encompass the CP level at which SCC would be expected to occur. The occurrence of cracking in a test coupon indicates levels of CP which will sustain SCC. SCC is prevented in the structure by application of a level of CP which did not sustain SCC.

대표청구항 ▼

[ What is claimed and desired to be secured by U.S. Letters Patent is:] [1.] A method of detecting stress corrosion cracking in a structure, comprising the steps of:a) placing a plurality of test coupons adjacent to said structure;b) applying a different level of cathodic protection to each of said

[ What is claimed and desired to be secured by U.S. Letters Patent is:] [1.] A method of detecting stress corrosion cracking in a structure, comprising the steps of:a) placing a plurality of test coupons adjacent to said structure;b) applying a different level of cathodic protection to each of said test coupons;c) applying a stress to each of said test coupons which is at least as great as the maximum stress which can occur in said structure;d) monitoring the temperature of said structure and controlling the temperature of each of said test coupons so that it matches the temperature of said structure;e) measuring the electrical resistance of each of said test coupons over time;f) detecting the occurrence of stress corrosion cracking in any of said test coupons as an increase in said electrical resistance; rein the levels of cathodic protection applied to said plurality of test coupons form a range which includes the level of cathodic protection at which stress corrosion cracking is expected to occur. [8.] A sensor for detecting stress corrosion cracking in buried pipelines, comprising:a) a three-dimensional framework constructed of a sturdy, non-conductive structural material;b) a plurality of C-ring coupons supported by said framework, each C-ring coupon having associated therewith:i) a temperature monitoring device for monitoring the temperature of test C-ring coupon;ii) a heating element affixed to said C-ring coupon;iii) an impressed current anode affixed to said framework in the vicinity of said C-ring coupon;iv) a reference electrode affixed to said framework in the vicinity of said C-ring coupon;v) a mechanism for applying a stress to said C-ring coupon.