Load Rate-Related Mechanical Properties of Steels and Alloys under Static and Cyclic Loading in Gaseous Hydrogen

• Published in: Strength of materials 2021-05, Vol.53 (3), p.430-439
• Main Authors: Balyts’kyi, O. I., Ivas’kevych, L. M.
• Format: Article
• Language: English
• Subjects: Alloys; Amplitudes; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crack propagation; Cyclic loads; Ductility; Fatigue failure; Heat resistant alloys; Hydrogen; Hydrogen embrittlement; Materials Science; Mechanical properties; Metal fatigue; Nickel alloys; Nickel base alloys; Nickel chromium molybdenum steels; Retained austenite; Solid Mechanics; Sorbite; Stainless steels; Steel
• ISSN: 0039-2316; 1573-9325
• DOI: 10.1007/s11223-021-00303-0

The hydrogen effect on strength, ductility, low-cycle life, and cyclic crack resistance parameters of steels of different structural classes and a heat-resistant nickel alloy is studied in the range of load rates of 0.01–100 mm/min, amplitudes and frequencies of low-cycle bending of 0.8–1.6% and 8.3·10 –3 – 8.3·10 –1 , respectively, and fatigue loading of beam specimens at frequencies of 0.5–50 Hz. A maximum hydrogen effect on the ductility of 38KhN3MFA (35NiCrMoV15-5) and 13Kh11N2V2MF (1.5Ni0.5Mo2W) steels and a KhN56MBYuD (56Ni6Mo4Nb) alloy was revealed in the range of load rates of 0.01–1 mm/min and for 05Kh11N23T3MR (23Ni1.5Mo3Ti) steel, it is at rates ≤ 0.1 mm/min. The hydrogen embrittlement of all materials in low-cycle bending and cyclic crack resistance tests was established to significantly weaken with the load frequency. With the strain amplitude, the hydrogen sensitivity of 38KhN3MFA steel (residual austenite and highly dispersed sorbite) decreases and that of 13Kh11N2V2MF steel increases, while the hydrogen embrittlement degree of austenitic materials is almost independent of the amplitude. A decrease in the load frequency from 50 to 5 Hz leads to a decrease in the cyclic crack resistance threshold and contributes to a significant crack acceleration in the presence of hydrogen in the middle section of the kinetic fatigue fracture diagrams.