| 2026 №03 (06) | 2026 №03 (01) |
"Suchasna Elektrometallurgiya" (Electrometallurgy Today), 2026, #3, 52-60 pages
Structure and properties of steam turbine blade metal under the conditions of repair restoration by laser cladding
O.M. Berdnikova
, Tiancheng An
E.O. Paton Electric Welding Institute of the NAS of Ukraine
11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine.
E-mail: omberdnikova@gmail.com
Abstract
The article presents the results of comprehensive experimental studies on the structure of deposited metal during the restoration of a steam turbine blade made of high-strength XM-25 steel using multilayer laser cladding with a powder of a similar composition. It was found that the laser cladding technology ensures producing a sound volumetric product with a deposited layer. As a result of cladding and subsequent heat treatment (holding at a temperature of 480 °C for 4 h), the deposited material exhibits satisfactory mechanical characteristics (σt = 1264…1274 MPa, σ0.2 = 1185…1208 MPa, δ = 12…13.5 %, ψ =54…61 %) and meets operational requirements. A homogeneous martensitic structure is formed throughout the volume of the metal, characterized by a gradient-free microhardness level (HV0.2 = 421…440 MPa), and carbide phase inclusions of < 1 μm size uniformly distributed through the metal volume. Fractographic studies have proven that ensuring the deposited metal strength characteristics is accompanied by realization of ductile fracture. Investigations at the dislocation level by the method of transmission electron microscopy established the formation of size-dispersed acicular structural components in the martensitic structure of the deposited metal with uniform distribution of the dislocation density. A substructure and particles of nano-sized thin-plate carbide precipitates are observed in the inner volumes of the structural components. This structure provides the best combination of mechanical properties and crack resistance for the deposited XM-25 metal. 17 Ref., 3 Tabl., 8 Fig.
Keywords: steam turbine blade, XM-25 steel, laser cladding, heat treatment, microhardness, microstructure, dislocation density, mechanical properties
Received: 08.06.2026
Received in revised form: 10.07.2026
Accepted: 14.07.2026
Posted online: 24.07.2026
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