... national standard GB3721-83 "magnetic powder flaw detection machine.2,This equipment should meet all the magnetic ... 400mm.8,The human-machine interface control system 11,Automatic demagnetization systemAttenuation type automatic demagnetization.12,Equipment has to ... 67 mm away from the surface)7,Demagnetization way Ultralow frequency demagnetization8,Demagnetization effect ≤160A/m(0.2mT9,Working ...