Study on the Cracking Behavior of Fasteners in Long-Term Service under Marine Environment
摘要
The environmental cracking mechanism of 18Cr2Ni4WA fasteners in long-term service under marine environment was studied by using slow strain tensile tests. In this paper, different simulated working conditions and varied strength grade of 18Cr2Ni4WA were used to clarify the relationships between long-term service cracking and corrosive medium Cl− and H. The results show that 18Cr2Ni4WA has stress corrosion sensitivity, and with the increase of strength, the stress corrosion sensitivity increases. Significantly, the presence of hydrogen accelerates material embrittlement, and leads to 18Cr2Ni4WA having higher stress cracking sensitivity. It can show that the existent of hydrogen in simulated seawater environment not only induces the crack to initiate, but also aggravate aggregated and diffused to crack tip, which finally cause rapid intergranular propagation of cracks.