Surface Crack Of Steel Bars Eddy Current Testing Methods

Steel bars is widely used in petroleum, chemical industry, bridges, buildings, etc, it is easy to have crack defects in the application, especially with the application of surface crack of the steel bars, it will directly affect the economic and safety, all countries in the world pay a lot of attentions to steel bars qualities testing. Due to production process reasons etc,there may exist surface crack of steel bars, if the steel bars working in changing stress conditions surface crack have a lot of influence on the fatigue life of steel bars,it will probably become the initiation source of fatigue crack, thus it will reduce the fatigue life of steel bars. Consequently, in order to prevent rods early break in working,it is necessary to test surface crack of steel bars.Eddy current testing as one of the five regular NDT testing means,the detection speed is very fast, it is very suitable for testing conductive surface and near surface crack. However, eddy current testing are also have limitations, such as test parameters have influence on ECT,that happened produce false signals, it puts forward the topic of how to use the best parameters of eddy current testing for surface crack of steel bars.In this paper, take the low carbon steel bars for example and apply the eddy current detector with placed type probe detection to test steel bars. Through the experimental method get laws between testing parameters,defects parameters and the signal. At the same time use wavelet to reduce the noise of signal get a higher SNR. Comprehensive analysis lab testing parameters and crack parameters relations with signals to get the laws.Based on the research of this paper, that conclusion between eddy current testing parameters, the crack parameters and the signal will lay a foundation for detection system design and the crack dimensions test.