Study on Stress Corrosion Cracking Sensitivity of CrNiMoV Steam Turbine Rotor Steels

Abstract:

The stress corrosion sensitivities of 25Cr2Ni2MoV, 26NiCrMoV10-10 and 30Cr2Ni4MoV low-pressure rotor steels in simulated nuclear steam turbine operation condition were investigated by slow strain rate test (SSRT), and the stress corrosion cracking (SCC) mechanisms were studied by optical microscope (OM), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Results revealed that the SCC sensitivity of 25Cr2Ni2MoV steel was highest in 3.5wt.%NaCl solution at 180°C, while the SCC sensitivity of 26NiCrMoV10-10 steel and 30Cr2Ni4MoV steel are similar. The SCC sensitivity of CrNiMoV steam turbine rotor steels could be decreased by the increase of Ni element and the decline of mechanical intensity. Cracks initiate from metal surface and then propagate to the inner metal, which showed a form of transgranular cracking.

• Periodical: Key Engineering Materials (Volume 795)
• Pages: 102-108
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.795.102
• Online since: March 2019
• Authors: Shu Xian Lin, Yu Hui Huang*, Fu Zhen Xuan, Shan Tung Tu
• Keywords: Low-Pressure Rotor Steel, Slow Strain Rate Test, Stress Corrosion Sensitivity

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