In addition to the hardness and toughness mentioned above, the materials used in non-magnetic drill collars also possess the following characteristics:
1. Low Magnetic Permeability: This is one of the most significant characteristics of non-magnetic drill collars. When the magnetic field strength is 800 A/m, its relative permeability μr is typically less than or equal to 1.010. This low permeability characteristic allows non-magnetic drill collars to provide a non-magnetic environment when magnetic measuring instruments are operating, thereby ensuring the accuracy of measurement data.
2. Corrosion Resistance: The materials used in non-magnetic drill collars also exhibit excellent corrosion resistance, particularly in terms of intergranular corrosion. This is due to the reasonable elemental ratio and refining process in the material, enabling non-magnetic drill collars to operate stably for extended periods in harsh drilling environments.
