Detection Method And Experimental Study Of Tank Bottom DC MFL Testing

Tank floor is made of ferromagnetic material, however, due to their operation in the condition of the change of environment and medium height all the year round, they inevitably suffer from various damage and other factors. Especially corrosion perforation, crack expanding and rive and so on by chemical corrosion and electrochemistry corrosion make medium leak and cause serious disaster and environment pollution. This is a big economic loss to the state economy.This paper first describes the background of the study tank bottom and tank floor significance of magnetic flux leakage testing. Comparing of different excitation characteristics of magnetic flux leakage test, and thus leads to the tank bottom DC magnetic flux leakage testing method. Then narrative the magnetic flux leakage testing of tank floor methods, application and development trend of narrative. Theory of the DC magnetic flux leakage testing methods are analyzed to illustrate the basic principles of DC magnetic flux leakage testing, and the introduction of finite element analysis of electromagnetic field theory. Excitation principle from the list of the types of magnetic flux leakage testing method, namely that the permanent magnet flux leakage testing, AC and DC magnetic flux leakage magnetic flux leakage testing and testing features of the excitation characteristics, from a different point of view of the DC magnetic flux leakage testing of factors, including the measured magnetization plate, the plate material and working conditions, defect type, the sensor lift-off values etc. Develop magnetic flux leakage technology for the inspection of tank floor, use the finite element method to have a reach with DC coil of magnetic flux leakage detection method , and analyses of the An circle number coil the influence of magnetized ability, determine the DC coil excitation optimal parameters, and the magnetic leakage field is obtained to defect component and the method of geometric parameter and defects of the relationship between lift-off value. At the last the condition of the laboratory experiment, for part of finite element analysis results were verified. Experimental results show that Dc magnetic flux leakage detection method is an effective local test methods, Dc magnetic flux leakage testing model variable magnetized ability can satisfy the needs of different thickness plate detection, and greatly improve the detection range.