In the operation of the turbines, there are problems of restoration and repair of worn blades experiencing large loads during the work. The inflow of foreign particles into the turbine leads to damage of blades’ leading edges, appearance of dints and change of their geometry. Production of one blade is very long and resource-intensive process that is the cause of its high cost. Different methods are used for their recovery, allowing to reduce the maintenance costs of the turbine, to increase its reliability and service life. Thus, to achieve these goals it is necessary to periodically repair the turbine.

A postgraduate student of the MEPhI Laser center D.P. Bykovskiy under the guidance of the Associate Professor of the Department № 37 V.N. Petrovsky has conducted research that have shown that the solution of this problem is possible to be achieved with the use of one kind of additive technologies – laser gas-powder surfacing.

Fig.1: sample of surfacing the blade tip

The process of restoring the blade’s shape consists of a consecutive application of rollers to each other at the damaged edge of the blade. Restoring surface is supplied by the metal powder coaxially with a radiation of CW fiber laser. After metallic powder melting and cooling a roller is formed on the blade’s surface. As a result, it is possible to apply one roller to another, creating a multi-layered structure of the desired height.

The MEPhI Laser center has conducted work on the selection of powder material, chose optimum technological modes (scan speed of the surface, consumption of powder, laser radiation power, gap between nozzle and blade, etc.) to form layers with properties not worse than those of the blade’s material.

Fig.2: process of blades recovery using laser gas-powder surfacing