Non - magnetic drill pipe is the auxiliary equipment of measurement while drilling in directional drilling. It is an important part of directional drilling tool in coal mine with low permeability and has the function of reducing the external interference of measuring device while drilling, signal transmission, power medium of bottom motor of conveying hole and power transmission of drilling rig. The characteristics of high tensile strength and good torsional performance provide the measuring system in the hole with no magnetic environment from the magnetic interference of the drilling tool. The magnetic field at the probing pipe is almost equal to the nearby geomagnetic field, so it can accurately distinguish the geomagnetic direction of the drilling hole and ensure the measuring accuracy of the measuring system.

The magneticless drill pipe is mainly used in the horizontal directional drilling system of coal mine tunnel. Compared with the magneticless drill pipe made of beryllium copper, the advantages of the special alloy magneticless drill pipe are as follows:

1. With no magnetic properties, under 20 oster conditions, its permeability is 1.00005-10001H/m in the strong magnetic field will not be magnetized;

2. Low elastic modulus: the elastic modulus of beryllium copper is 1.35x105MPa, while the elastic modulus of this alloy is 1.17x105MPa, which is 1.15 times of that of beryllium copper.

3, high strength to mass ratio: the yield strength of this alloy is 840MPa, its strength to mass ratio is 1.8 times that of beryllium copper.

4, good plasticity: fracture elongation is 2~5 times that of beryllium copper, can reach the level of 120 steel;

5, corrosion resistance: with anti-corrosion and downhole environment adaptability, can work in hydrogen sulfide acid high corrosion environment, its corrosion resistance is better than beryllium copper; 6. Corrosion resistance fatigue: this alloy will not suffer from corrosion fatigue, and its fatigue performance is the same in the drilling fluid environment as in the air. Its corrosion resistance is better than beryllium copper.