[5A1] Magnetic NDT of the microstructure of steels for oil and gas applications
A Regan¹, J Wilson¹, N Bonadeo², J Etcheverry², G Echaniz² and A Peyton¹
¹University of Manchester, UK
²Tenaris, Argentina
There are well-documented links between the magnetic properties of steels and their mechanical and microstructural parameters. Consequently, magnetic testing provides a potential route for the non-destructive testing of these parameters. This study considers the magnetic properties of mechanically hard oil and gas steels at various stages of their heat treatment process in order to understand the potential of magnetic techniques for microstructure NDT in these applications.
The mechanically hard steels used in oil and gas applications are often difficult to represent using typical models for magnetic hysteresis, often with a sharp corner that is not well represented. Therefore, a new modified form of the widely used Jiles-Atherton hysteresis model has been developed in order to better describe these materials. The model was applied to two different oil and gas steels at different stages of their heat treatments and compared with closed magnetic circuit measurement of the actual hysteresis loop to confirm its efficacy.
This hysteresis model was also used to develop finite element models for the open magnetic circuit configuration of the type that could be adapted for field use. The results of modelling have been compared to experimental results.
The mechanically hard steels used in oil and gas applications are often difficult to represent using typical models for magnetic hysteresis, often with a sharp corner that is not well represented. Therefore, a new modified form of the widely used Jiles-Atherton hysteresis model has been developed in order to better describe these materials. The model was applied to two different oil and gas steels at different stages of their heat treatments and compared with closed magnetic circuit measurement of the actual hysteresis loop to confirm its efficacy.
This hysteresis model was also used to develop finite element models for the open magnetic circuit configuration of the type that could be adapted for field use. The results of modelling have been compared to experimental results.
