Corrosion inspection of nickel alloys, esp. turbine blades - where variation in magnetism produces micro voltage in nondestructive test

摘要

Device for testing the state of corrosion of nickel alloy objects, uses a socket contg. a sensor bar connected to a strain gauge transducer which emits an electric signal proportional to the axial tensile stress on the sensor bar. The free end of the sensor bar is fitted with a permanent magnet surrounded by a distance ring made of non magnetic material, the ring being axially adjustable on the socket; and the free end of the ring projects beyond the free end of the magnet and can be applied to the surface of the object being tested. A long magnet is pref. used which is surrounded by a ring consisting of a tube which can be screwed onto the socket. Used, e.g. in the non-destructive inspection of a degree of corrosion of nickel superalloy turbine blades used in jet engines or power station generating plant. A portable appts. suitable for periodic inspection of blades in situ. is provided.