Investigation of microstructure and properties of low-carbon steel during ultrasonic-assisted laser welding and cladding

The paper shows the possibilities of using ultrasonic vibrations in the processes of laser welding and cladding. Optical and electron microscopy, local elemental analysis, X-ray tomography, and series of tensile tests were used to investigate the effect of vibrations on the respective processes. It is shown that ultrasonic vibrations can be used in two different ways: ultrasonic online processing during welding and surfacing and post processing of the finished weld seam and cladded metal. In the first case, ultrasonic effect leads to reduction of the weld seam thickness and an increase of the depth of weld penetration. In the second case, ultrasonic post-treatment of the samples produced by layer-by-layer direct laser wire deposition results in an increase of tensile strength of the cladded material up to 1.3 times. It is shown that the effect is caused by formation of an oriented thin-plate structures on the surface of the samples.