A Novel Characteristic Method on Fatigue Crack Growth of N80 Casing Drilling Steel

Abstract

Electrical parameters and low-frequency noise test were measured for N80 steel casing drilling, through extracting low-frequency parameters and combining with conventional fatigue crack growth characterization methods and analyzing their morphology. After fatigue crack growth, the results showed that: (1) Electrical parameters of N80 increase, and power spectral density of 1/f noise increases two orders of magnitude. (2) Values of γ and B are significantly increased, indicating that the process of fatigue produced more cracks, defects, and combination centers, from the mechanism of fatigue crack growth of N80, defects and cracks resulting from fatigue are the numbers of kind of fluctuations. In essence, low-frequency noise is a type of fluctuations, which show that low-frequency noise as the characterization of non-destructive., which can serve as a viable tool to study the defects and the characterization of defects.