ISSN 3041-1815. Physicochemical Mechanics of Materials. 2026.
Volume 62, Issue 4
Influence of hydrogen charging on mechanical properties and fracture mechanism of operated 30KhN3M1FA steel
Solovei P. R. 
Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, Lviv, Ukraine. (https://ror.org/02jv3yx22)
Krechkovska H. V.
Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, Lviv, Ukraine. (https://ror.org/02jv3yx22)
Lviv Polytechnic National University, Lviv, Ukraine. (https://ror.org/0542q3127)
Student O. Z.
Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, Lviv, Ukraine. (https://ror.org/02jv3yx22)
Zvirko O. I.
Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, Lviv, Ukraine. (https://ror.org/02jv3yx22)
Keywords
30KhN3M1FA heat-resistant steel, operational degradation, mechanical properties, hydrogen charging effects, failure mechanism.
Cite as
Solovei P. R., Krechkovska H. V., Student O. Z., and Zvirko O. I. Influence of hydrogen charging on mechanical properties and fracture mechanism of operated 30KhN3M1FA steel. Physicochemical Mechanics of Materials. 2026. 62(4), 81-89.
Abstract
Long-term operation of steam turbine rotor (STR) elements in difficult temperature-force conditions and under the influence of technological environments causes degradation of steels with loss of properties that guaranteed their operability at the beginning of operation. The mechanical properties of 30KhN3M1FA steel after 1.22×105 h of operation in the STR disk, their change after steel hydrogen charging were determined, and fractographic features caused by hydrogen were identified. Uniaxial tensile tests of the tangential- and radial-oriented smooth specimens in air, in a model environment of extreme condensate, and in air, but after specimen preliminary hydrogen charging, were used to certify the steel. It was established that even after the operation, the strength and ductility characteristics of the steel met the regulatory requirements for its initial state. Despite the practical invariance of the steel strength after tests in a model environment or in air after preliminary hydrogen charging, its ductility characteristics decreased, and under the influence of hydrogen charging, ceased to meet the recommended values. The fractographic studies showed that under the influence of hydrogen accumulated along the interfaces of non-metallic inclusions with the matrix, brittle transgranular cleavages were initiated, which weakened the cross-section of the specimens and limited their ability to deform plastically. Therefore, hydrogen charging, which cannot be avoided during long-term operation of the STR, will contribute to hydrogen embrittlement of the steel near non-metallic inclusions, which will lead to premature failure of the disk.