Effect of ultrasonic vibration on quality and properties of laser cladding EA4T steel

The surface of EA4T steel was repaired by ultrasonic vibration assisted laser cladding.The influence of ultrasonic vibration on the forming quality, microstructure and phase composition of laser cladding of EA4T steel were compared and analyzed by optical microscopy (OM),scanning electron microscopy(SEM),X ray diffraction(XRD),and the microhardness of the cladding layer and matrix was tested by microhardness tester.The results show that the cladding forming quality is improved, and the dendritic structure with strong original orientation is broken under the effect of ultrasonic vibration,which reduces the segregation of dendrites within the cladding layer.At the same time,ultrasonic vibration refined grain, promotes the precipitation of Cr23C6 carbide on the dendrites, but it does not change the phase composition of cladding layer.Compared with that without ultrasonic vibration applied,the microhardness distribution of cladding layer is more uniform under the ultrasonic vibration, the average microhardness of cladding layer is increased by 126.2HV0.2,and the average microhardness of heat-affected zone is decreased by 31.2HV0.2