• FerroChem NDT Systems Private Limited

Demagnetiser for Coil Springs After MPI

Demagnetisation is generally recommended after MPI as the residual magnetism may interfere with sensitive instruments and pose difficulties for further mechanical operations. Demagnetisation of coil springs is a job with concealed difficulties. Coil spring, which is magnetised by direct contact method, does not show poles after testing. However, when central conductor is used for detection of longitudinal cracks, poles are formed at the ends of the coil. Demagnetising such a coil is not feasible by letting it pass through a conventional demagnetising coil with its axis parallel to that of the demagnetising coil. In order to thoroughly demagnetise, a coil spring, after magnetisation by using central conductor, the spring is rolled through the demagnetising coil. However, the axis of spring should be perpendicular to the axis of demagnetising coil. FerroChem NDT Systems has recently developed a demagnetising coil for a coil spring manufacturer in Malaysia. The spring is rolled through the demagnetising coil by making use of slanting structure. The demagnetising coil is tilted in the same angle as the slanting structure to ensure that the magnetic field of the demagnetising coil is parallel to the axis of the spring. The photograph shows the arrangement as supplied. Structure suitable to meet tailor made requirements can be made available. Other features of the demagnetising coils such as automatic cut-off are also provided.