Vitaliy Dzhemelinskyi, Dmytro Lesyk, Olexiy Goncharuk, Oleksandr Dаnyleikо

Surface hardening and finishing of metallic products by hybrid laser­ultrasonic treatment

Eastern-European Journal of Enterprise Technologies 1/12(91), с. 35-42


Theoretical and experimental study of the possibilities of using laser heat treatment (LHT) combined with ultrasonic impact treatment (UIT) for surface hardening and finishing of metallic products was carried out. The austenization temperature range (1,050...1,350 °C) at different speeds (50...150 mm/min) of LHT without surface melting by the scanning laser beam, as well as the beginning (~360 °C) and end (~245 °C) temperatures of the martensitic transformation during the specimen cooling were determined. As a result, it allows narrowing the range of optimum LHT regimes, providing the surface hardness of 800...1,000 HV and the hardening depth of 200...400 μm of the surface layer. Experimental studies have confirmed that the determined magnitude of temperature on the specimen surface of AISI 1045 steel correlates well with the heating temperature measured by the laser pyrometer. As a consequence, this provides the ability to determine the application distance of the ultrasonic tool during cooling in the laser surface hardening of metallic surfaces.
The comparative analysis of the microhardness of the surface layer and the surface roughness of the samples treated by LHT, UIT, combined and hybrid laser-ultrasonic treatment was carried out. It was found that the hybrid laser-ultrasonic treatment allowed increasing the microhardness of surface layers more than 3 times and reducing the roughness parameter Ra approximately 3 times compared to the initial state, provided favorable conditions to trap oil on the product surface. Thus, there are reasons to assert the possibility of using the hybrid LHT+UIT for surface hardening and finishing of the large-sized products that work in extreme conditions


laser-ultrasonic hardening; AISI 1045 steel; thermo-kinetic model; thermo-physical model; hardness; roughness