Huang Liangliang, Zhang Lin
College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
Materials (Basel). 2024 Nov 17;17(22):5612. doi: 10.3390/ma17225612.
The fatigue characteristics of notched specimens of L360 pipeline steel in hydrogen and nitrogen environments were investigated by high cycle fatigue life tests and fatigue crack growth rate tests. The fracture morphology in the nitrogen environment was dominated by microcracks and fatigue strips. The fatigue fracture had distinctly different regions in the hydrogen environment. The outer region of the fracture in the hydrogen environment was similar to the nitrogen environment, but a large number of hydrogen embrittlement features were found in the inner region. The fatigue crack growth rate tests were analyzed in conjunction with fatigue life tests. It was found that more fatigue cycles were required to achieve the stress intensity factor ΔK for rapid hydrogen-promoted crack propagation at lower stress. The region with hydrogen embrittlement features increases with decreasing stress.
通过高周疲劳寿命试验和疲劳裂纹扩展速率试验，研究了L360管线钢缺口试样在氢气和氮气环境中的疲劳特性。氮气环境中的断口形貌以微裂纹和疲劳条带为主。氢气环境中的疲劳断口有明显不同的区域。氢气环境中断口的外部区域与氮气环境相似，但内部区域发现了大量氢脆特征。结合疲劳寿命试验对疲劳裂纹扩展速率试验进行了分析。发现在较低应力下，实现快速氢促进裂纹扩展所需的应力强度因子ΔK需要更多的疲劳循环。具有氢脆特征的区域随应力降低而增加。
