Fatigue and Corrosion Fatigue of 18Ni Maraging Steel

This study focused on the fatigue and corrosion fatigue of maraging steel 18Ni (250). The 18Ni (250) samples were tested for axial fatigue in air and 3.5% NaCl solution. The effects of loading frequency and stress ratio on the fatigue strength of 18Ni (250) were studied. In air, the loading frequency was 10 Hz, and the stress ratio was 0.5. However, three loading methods were used in the 3.5% NaCl solution: (i) the loading frequency of 1 Hz and stress ratio of 0.5; (ii) the loading frequency of 1 Hz and stress ratio 0.1, and (iii) the loading frequency 5 Hz and stress ratio 0.5. The corrosion fatigue strength of samples in the 3.5% NaCl solution was 63.3% lower than that of the samples in air. The fractures in the samples were observed after the test.

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1. This study was funded by the General Program of National Natural Science Foundation of China (‘Study on the Design and Life Calculation Method for the Maraging Steel Sphere of Full-ocean-depth Manned Submersible’ (Grant No. 51679133); the State Key Program of National Natural Science of China (‘Structural Reliability Analysis on the Spherical Hull of Deepsea Manned Submersibles;’ Grant No. 51439004), the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No. 19KJA530002), and Graduate Research and Practice Innovation in Jiangsu Province (Grant No. SJCX19_0608).

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2. Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2021).