V. N. Petrovskiy

Specific features of the welding of metals by radiation of high-power fiber laser

The properties of the plasma that results from the laser welding of metals at various powers of the 10-kW ytterbium-doped fiber laser are experimentally studied. A projection system with an image intensifier based on a copper-vapor laser is employed for the direct observation of metal surface in the course of the laser welding in the presence of the high-intensity background illumination. A method for the shadow photographing is proposed for the analysis of the presence of metal vapor in plasma, since such vapor can lead to the reflection of the laser radiation in the course of welding.

Vapor?plasma plume investigation during high-power fiber laser welding

This work is devoted to the investigation of the laser–matter interaction during up to 20 kW ytterbium fiber laser welding of thick mild steel plates. The plume attenuation of a probe 1.3 μm wavelength diode laser beam as well as of continuous radiation in the 250–600 nm wavelength range was measured during welding with and without Ar shielding gas supply. The measured results allow the calculation of the average size and concentration of fine condensed metal particles in different plume areas using the multi-wavelength method and the Mie scattering theory. The plume temperature, which determines the condensation conditions, was measured by means of Fe I atom spectral line emission registration. The spatial distribution of the extinction coefficient in the welding plume was measured and the plume attenuation of the high-power fiber laser beam during the welding process was estimated.

Technology of polishing of titanium surface using the fiber-laser radiation

The effect of the radiation of the pulsed fiber laser on the surfaces of cylindrical samples made of the VT16 titanium alloy is studied. It is demonstrated that the irradiation at appropriate parameters of the laser radiation in the inert-gas (argon) atmosphere leads to an increase in the microhardness of the surface layer and a decrease in the surface roughness of the irradiated samples by a factor of five in comparison with the roughness of the original samples.

Spectral diagnostics of a vapor-plasma plume produced during welding with a high-power ytterbium fiber laser

We have conducted spectroscopic studies of the welding plasma formed in the process of welding with an ytterbium fiber laser delivering output power of up to 20 kW. The influence of shielding gases (Ar, He) on different parts of the welding plume is investigated. The absorption coefficient of the laser radiation by the welding-plume plasma is estimated. Scattering of 532-nm probe radiation from particles of the condensed metal vapor within the caustic of a high-power fiber laser beam is measured. Based on the obtained results, conclusions are made on the influence of the plasma formation and metal vapor condensation on the radiation of the high-power fiber laser and the stability of the welding process.

Spectral diagnostics of a vapor-plasma plume produced during welding titanium with a high-power ytterbium fiber laser

We have conducted spectroscopic studies of the welding plasma formed in the process of welding with an ytterbium fiber laser delivering output power of up to 20 kW. The influence of shielding gases (Ar, He) on different parts of the welding plume is investigated. The absorption coefficient of the laser radiation by the welding-plume plasma is estimated. Scattering of 532-nm probe radiation from particles of the condensed metal vapor within the caustic of a high-power fiber laser beam is measured. Based on the obtained results, conclusions are made on the influence of the plasma formation and metal vapor condensation on the radiation of the high-power fiber laser and the stability of the welding process.

Change of phase composition of metals by the radiation of the fiber laser for management of their magnetic characteristics

Main technological parameters of heat treatment of ferromagnetic alloy samples of special stainless steel were experimentally determined in order to create the paramagnetic zone of a given size there.