The ESP protecor shaft is mainly used for fixed impeller of electric submersible protecor, with the function of transmission, fixing and supporting. The main material for the shaft is Monel alloy K500. It has special mechanical properties of excellent resistance to torsion and tensile, good properties of high temperature and corrosion resistance in the complex conditions, which allows the protector to work at maximum strength and have satisfied functioning life under load. This material has been long and widely used. Nickel component is one of the main components of the shaft, and its accurate determination is particularly important.